文件 AWS 開發套件範例 GitHub 儲存庫中有更多可用的 [AWS SDK 範例](https://github.com/awsdocs/aws-doc-sdk-examples)。

本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。

# 使用適用於 JavaScript 的 SDK (v3) 的 Lambda 範例
<a name="javascript_3_lambda_code_examples"></a>

下列程式碼範例示範如何搭配 Lambda 使用 適用於 JavaScript 的 AWS SDK (v3) 來執行動作和實作常見案例。

*基本概念*是程式碼範例，這些範例說明如何在服務內執行基本操作。

*Actions* 是大型程式的程式碼摘錄，必須在內容中執行。雖然動作會告訴您如何呼叫個別服務函數，但您可以在其相關情境中查看內容中的動作。

*案例*是向您展示如何呼叫服務中的多個函數或與其他 AWS 服務組合來完成特定任務的程式碼範例。

每個範例均包含完整原始碼的連結，您可在連結中找到如何設定和執行內容中程式碼的相關指示。

**Topics**
+ [開始使用](#get_started)
+ [基本概念](#basics)
+ [動作](#actions)
+ [案例](#scenarios)
+ [無伺服器範例](#serverless_examples)

## 開始使用
<a name="get_started"></a>

### Hello Lambda
<a name="lambda_Hello_javascript_3_topic"></a>

下列程式碼範例示範如何開始使用 Lambda。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
import { LambdaClient, paginateListFunctions } from "@aws-sdk/client-lambda";

const client = new LambdaClient({});

export const helloLambda = async () => {
  const paginator = paginateListFunctions({ client }, {});
  const functions = [];

  for await (const page of paginator) {
    const funcNames = page.Functions.map((f) => f.FunctionName);
    functions.push(...funcNames);
  }

  console.log("Functions:");
  console.log(functions.join("\n"));
  return functions;
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [ListFunctions](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/ListFunctionsCommand)。

## 基本概念
<a name="basics"></a>

### 了解基本概念
<a name="lambda_Scenario_GettingStartedFunctions_javascript_3_topic"></a>

以下程式碼範例顯示做法：
+ 建立 IAM 角色和 Lambda 函數，然後上傳處理常式程式碼。
+ 調用具有單一參數的函數並取得結果。
+ 更新函數程式碼並使用環境變數進行設定。
+ 調用具有新參數的函數並取得結果。顯示傳回的執行日誌。
+ 列出您帳戶的函數，然後清理相關資源。

如需詳細資訊，請參閱[使用主控台建立 Lambda 函數](https://docs.aws.amazon.com/lambda/latest/dg/getting-started-create-function.html)。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda/scenarios/basic#code-examples)中設定和執行。
建立 AWS Identity and Access Management (IAM) 角色，授予 Lambda 寫入日誌的許可。  

```
    logger.log(`Creating role (${NAME_ROLE_LAMBDA})...`);
    const response = await createRole(NAME_ROLE_LAMBDA);

import { AttachRolePolicyCommand, IAMClient } from "@aws-sdk/client-iam";

const client = new IAMClient({});

/**
 *
 * @param {string} policyArn
 * @param {string} roleName
 */
export const attachRolePolicy = (policyArn, roleName) => {
  const command = new AttachRolePolicyCommand({
    PolicyArn: policyArn,
    RoleName: roleName,
  });

  return client.send(command);
};
```
建立 Lambda 函數並上傳處理常式程式碼。  

```
const createFunction = async (funcName, roleArn) => {
  const client = new LambdaClient({});
  const code = await readFile(`${dirname}../functions/${funcName}.zip`);

  const command = new CreateFunctionCommand({
    Code: { ZipFile: code },
    FunctionName: funcName,
    Role: roleArn,
    Architectures: [Architecture.arm64],
    Handler: "index.handler", // Required when sending a .zip file
    PackageType: PackageType.Zip, // Required when sending a .zip file
    Runtime: Runtime.nodejs16x, // Required when sending a .zip file
  });

  return client.send(command);
};
```
調用具有單一參數的函數並取得結果。  

```
const invoke = async (funcName, payload) => {
  const client = new LambdaClient({});
  const command = new InvokeCommand({
    FunctionName: funcName,
    Payload: JSON.stringify(payload),
    LogType: LogType.Tail,
  });

  const { Payload, LogResult } = await client.send(command);
  const result = Buffer.from(Payload).toString();
  const logs = Buffer.from(LogResult, "base64").toString();
  return { logs, result };
};
```
更新函數程式碼並設定具有環境變數的 Lambda 環境。  

```
const updateFunctionCode = async (funcName, newFunc) => {
  const client = new LambdaClient({});
  const code = await readFile(`${dirname}../functions/${newFunc}.zip`);
  const command = new UpdateFunctionCodeCommand({
    ZipFile: code,
    FunctionName: funcName,
    Architectures: [Architecture.arm64],
    Handler: "index.handler", // Required when sending a .zip file
    PackageType: PackageType.Zip, // Required when sending a .zip file
    Runtime: Runtime.nodejs16x, // Required when sending a .zip file
  });

  return client.send(command);
};

const updateFunctionConfiguration = (funcName) => {
  const client = new LambdaClient({});
  const config = readFileSync(`${dirname}../functions/config.json`).toString();
  const command = new UpdateFunctionConfigurationCommand({
    ...JSON.parse(config),
    FunctionName: funcName,
  });
  const result = client.send(command);
  waitForFunctionUpdated({ FunctionName: funcName });
  return result;
};
```
列出您帳戶的函數。  

```
const listFunctions = () => {
  const client = new LambdaClient({});
  const command = new ListFunctionsCommand({});

  return client.send(command);
};
```
刪除 IAM 角色與 Lambda 函數。  

```
import { DeleteRoleCommand, IAMClient } from "@aws-sdk/client-iam";

const client = new IAMClient({});

/**
 *
 * @param {string} roleName
 */
export const deleteRole = (roleName) => {
  const command = new DeleteRoleCommand({ RoleName: roleName });
  return client.send(command);
};

/**
 * @param {string} funcName
 */
const deleteFunction = (funcName) => {
  const client = new LambdaClient({});
  const command = new DeleteFunctionCommand({ FunctionName: funcName });
  return client.send(command);
};
```
+ 如需 API 詳細資訊，請參閱《*適用於 JavaScript 的 AWS SDK API 參考*》中的下列主題。
  + [CreateFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/CreateFunctionCommand)
  + [DeleteFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/DeleteFunctionCommand)
  + [GetFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/GetFunctionCommand)
  + [Invoke](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/InvokeCommand)
  + [ListFunctions](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/ListFunctionsCommand)
  + [UpdateFunctionCode](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/UpdateFunctionCodeCommand)
  + [UpdateFunctionConfiguration](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/UpdateFunctionConfigurationCommand)

## 動作
<a name="actions"></a>

### `CreateFunction`
<a name="lambda_CreateFunction_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `CreateFunction`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const createFunction = async (funcName, roleArn) => {
  const client = new LambdaClient({});
  const code = await readFile(`${dirname}../functions/${funcName}.zip`);

  const command = new CreateFunctionCommand({
    Code: { ZipFile: code },
    FunctionName: funcName,
    Role: roleArn,
    Architectures: [Architecture.arm64],
    Handler: "index.handler", // Required when sending a .zip file
    PackageType: PackageType.Zip, // Required when sending a .zip file
    Runtime: Runtime.nodejs16x, // Required when sending a .zip file
  });

  return client.send(command);
};
```
+  如需 API 詳細資訊，請參閱《*適用於 JavaScript 的 AWS SDK API 參考*》中的「[CreateFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/CreateFunctionCommand)」。

### `DeleteFunction`
<a name="lambda_DeleteFunction_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `DeleteFunction`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
/**
 * @param {string} funcName
 */
const deleteFunction = (funcName) => {
  const client = new LambdaClient({});
  const command = new DeleteFunctionCommand({ FunctionName: funcName });
  return client.send(command);
};
```
+  如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [DeleteFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/DeleteFunctionCommand)。

### `GetFunction`
<a name="lambda_GetFunction_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `GetFunction`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const getFunction = (funcName) => {
  const client = new LambdaClient({});
  const command = new GetFunctionCommand({ FunctionName: funcName });
  return client.send(command);
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [GetFunction](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/GetFunctionCommand)。

### `Invoke`
<a name="lambda_Invoke_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `Invoke`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const invoke = async (funcName, payload) => {
  const client = new LambdaClient({});
  const command = new InvokeCommand({
    FunctionName: funcName,
    Payload: JSON.stringify(payload),
    LogType: LogType.Tail,
  });

  const { Payload, LogResult } = await client.send(command);
  const result = Buffer.from(Payload).toString();
  const logs = Buffer.from(LogResult, "base64").toString();
  return { logs, result };
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [Invoke](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/InvokeCommand)。

### `ListFunctions`
<a name="lambda_ListFunctions_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `ListFunctions`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const listFunctions = () => {
  const client = new LambdaClient({});
  const command = new ListFunctionsCommand({});

  return client.send(command);
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [ListFunctions](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/ListFunctionsCommand)。

### `UpdateFunctionCode`
<a name="lambda_UpdateFunctionCode_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `UpdateFunctionCode`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const updateFunctionCode = async (funcName, newFunc) => {
  const client = new LambdaClient({});
  const code = await readFile(`${dirname}../functions/${newFunc}.zip`);
  const command = new UpdateFunctionCodeCommand({
    ZipFile: code,
    FunctionName: funcName,
    Architectures: [Architecture.arm64],
    Handler: "index.handler", // Required when sending a .zip file
    PackageType: PackageType.Zip, // Required when sending a .zip file
    Runtime: Runtime.nodejs16x, // Required when sending a .zip file
  });

  return client.send(command);
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [UpdateFunctionCode](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/UpdateFunctionCodeCommand)。

### `UpdateFunctionConfiguration`
<a name="lambda_UpdateFunctionConfiguration_javascript_3_topic"></a>

以下程式碼範例顯示如何使用 `UpdateFunctionConfiguration`。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/lambda#code-examples)中設定和執行。

```
const updateFunctionConfiguration = (funcName) => {
  const client = new LambdaClient({});
  const config = readFileSync(`${dirname}../functions/config.json`).toString();
  const command = new UpdateFunctionConfigurationCommand({
    ...JSON.parse(config),
    FunctionName: funcName,
  });
  const result = client.send(command);
  waitForFunctionUpdated({ FunctionName: funcName });
  return result;
};
```
+  如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [UpdateFunctionConfiguration](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/lambda/command/UpdateFunctionConfigurationCommand)。

## 案例
<a name="scenarios"></a>

### 使用 Lambda 函數自動確認已知使用者
<a name="cross_CognitoAutoConfirmUser_javascript_3_topic"></a>

下列程式碼範例示範如何使用 Lambda 函式自動確認已知的 Amazon Cognito 使用者。
+ 設定使用者集區以呼叫 `PreSignUp` 觸發條件的 Lambda 函數。
+ 使用 Amazon Cognito 註冊使用者。
+ Lambda 函數會掃描 DynamoDB 資料表，並自動確認已知使用者。
+ 以新使用者身分登入，然後清除資源。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/wkflw-pools-triggers#code-examples)中設定和執行。
設定互動式 "Scenario" 執行。JavaScript (v3) 範例會共用案例執行器，以簡化複雜的範例。完整的原始程式碼位於 GitHub。  

```
import { AutoConfirm } from "./scenario-auto-confirm.js";

/**
 * The context is passed to every scenario. Scenario steps
 * will modify the context.
 */
const context = {
  errors: [],
  users: [
    {
      UserName: "test_user_1",
      UserEmail: "test_email_1@example.com",
    },
    {
      UserName: "test_user_2",
      UserEmail: "test_email_2@example.com",
    },
    {
      UserName: "test_user_3",
      UserEmail: "test_email_3@example.com",
    },
  ],
};

/**
 * Three Scenarios are created for the workflow. A Scenario is an orchestration class
 * that simplifies running a series of steps.
 */
export const scenarios = {
  // Demonstrate automatically confirming known users in a database.
  "auto-confirm": AutoConfirm(context),
};

// Call function if run directly
import { fileURLToPath } from "node:url";
import { parseScenarioArgs } from "@aws-doc-sdk-examples/lib/scenario/index.js";

if (process.argv[1] === fileURLToPath(import.meta.url)) {
  parseScenarioArgs(scenarios, {
    name: "Cognito user pools and triggers",
    description:
      "Demonstrate how to use the AWS SDKs to customize Amazon Cognito authentication behavior.",
  });
}
```
此案例展示如何自動確認已知使用者。它會協調範例步驟。  

```
import { wait } from "@aws-doc-sdk-examples/lib/utils/util-timers.js";
import {
  Scenario,
  ScenarioAction,
  ScenarioInput,
  ScenarioOutput,
} from "@aws-doc-sdk-examples/lib/scenario/scenario.js";

import {
  getStackOutputs,
  logCleanUpReminder,
  promptForStackName,
  promptForStackRegion,
  skipWhenErrors,
} from "./steps-common.js";
import { populateTable } from "./actions/dynamodb-actions.js";
import {
  addPreSignUpHandler,
  deleteUser,
  getUser,
  signIn,
  signUpUser,
} from "./actions/cognito-actions.js";
import {
  getLatestLogStreamForLambda,
  getLogEvents,
} from "./actions/cloudwatch-logs-actions.js";

/**
 * @typedef {{
 *   errors: Error[],
 *   password: string,
 *   users: { UserName: string, UserEmail: string }[],
 *   selectedUser?: string,
 *   stackName?: string,
 *   stackRegion?: string,
 *   token?: string,
 *   confirmDeleteSignedInUser?: boolean,
 *   TableName?: string,
 *   UserPoolClientId?: string,
 *   UserPoolId?: string,
 *   UserPoolArn?: string,
 *   AutoConfirmHandlerArn?: string,
 *   AutoConfirmHandlerName?: string
 * }} State
 */

const greeting = new ScenarioOutput(
  "greeting",
  (/** @type {State} */ state) => `This demo will populate some users into the \
database created as part of the "${state.stackName}" stack. \
Then the AutoConfirmHandler will be linked to the PreSignUp \
trigger from Cognito. Finally, you will choose a user to sign up.`,
  { skipWhen: skipWhenErrors },
);

const logPopulatingUsers = new ScenarioOutput(
  "logPopulatingUsers",
  "Populating the DynamoDB table with some users.",
  { skipWhenErrors: skipWhenErrors },
);

const logPopulatingUsersComplete = new ScenarioOutput(
  "logPopulatingUsersComplete",
  "Done populating users.",
  { skipWhen: skipWhenErrors },
);

const populateUsers = new ScenarioAction(
  "populateUsers",
  async (/** @type {State} */ state) => {
    const [_, err] = await populateTable({
      region: state.stackRegion,
      tableName: state.TableName,
      items: state.users,
    });
    if (err) {
      state.errors.push(err);
    }
  },
  {
    skipWhen: skipWhenErrors,
  },
);

const logSetupSignUpTrigger = new ScenarioOutput(
  "logSetupSignUpTrigger",
  "Setting up the PreSignUp trigger for the Cognito User Pool.",
  { skipWhen: skipWhenErrors },
);

const setupSignUpTrigger = new ScenarioAction(
  "setupSignUpTrigger",
  async (/** @type {State} */ state) => {
    const [_, err] = await addPreSignUpHandler({
      region: state.stackRegion,
      userPoolId: state.UserPoolId,
      handlerArn: state.AutoConfirmHandlerArn,
    });
    if (err) {
      state.errors.push(err);
    }
  },
  {
    skipWhen: skipWhenErrors,
  },
);

const logSetupSignUpTriggerComplete = new ScenarioOutput(
  "logSetupSignUpTriggerComplete",
  (
    /** @type {State} */ state,
  ) => `The lambda function "${state.AutoConfirmHandlerName}" \
has been configured as the PreSignUp trigger handler for the user pool "${state.UserPoolId}".`,
  { skipWhen: skipWhenErrors },
);

const selectUser = new ScenarioInput(
  "selectedUser",
  "Select a user to sign up.",
  {
    type: "select",
    choices: (/** @type {State} */ state) => state.users.map((u) => u.UserName),
    skipWhen: skipWhenErrors,
    default: (/** @type {State} */ state) => state.users[0].UserName,
  },
);

const checkIfUserAlreadyExists = new ScenarioAction(
  "checkIfUserAlreadyExists",
  async (/** @type {State} */ state) => {
    const [user, err] = await getUser({
      region: state.stackRegion,
      userPoolId: state.UserPoolId,
      username: state.selectedUser,
    });

    if (err?.name === "UserNotFoundException") {
      // Do nothing. We're not expecting the user to exist before
      // sign up is complete.
      return;
    }

    if (err) {
      state.errors.push(err);
      return;
    }

    if (user) {
      state.errors.push(
        new Error(
          `The user "${state.selectedUser}" already exists in the user pool "${state.UserPoolId}".`,
        ),
      );
    }
  },
  {
    skipWhen: skipWhenErrors,
  },
);

const createPassword = new ScenarioInput(
  "password",
  "Enter a password that has at least eight characters, uppercase, lowercase, numbers and symbols.",
  { type: "password", skipWhen: skipWhenErrors, default: "Abcd1234!" },
);

const logSignUpExistingUser = new ScenarioOutput(
  "logSignUpExistingUser",
  (/** @type {State} */ state) => `Signing up user "${state.selectedUser}".`,
  { skipWhen: skipWhenErrors },
);

const signUpExistingUser = new ScenarioAction(
  "signUpExistingUser",
  async (/** @type {State} */ state) => {
    const signUp = (password) =>
      signUpUser({
        region: state.stackRegion,
        userPoolClientId: state.UserPoolClientId,
        username: state.selectedUser,
        email: state.users.find((u) => u.UserName === state.selectedUser)
          .UserEmail,
        password,
      });

    let [_, err] = await signUp(state.password);

    while (err?.name === "InvalidPasswordException") {
      console.warn("The password you entered was invalid.");
      await createPassword.handle(state);
      [_, err] = await signUp(state.password);
    }

    if (err) {
      state.errors.push(err);
    }
  },
  { skipWhen: skipWhenErrors },
);

const logSignUpExistingUserComplete = new ScenarioOutput(
  "logSignUpExistingUserComplete",
  (/** @type {State} */ state) =>
    `"${state.selectedUser} was signed up successfully.`,
  { skipWhen: skipWhenErrors },
);

const logLambdaLogs = new ScenarioAction(
  "logLambdaLogs",
  async (/** @type {State} */ state) => {
    console.log(
      "Waiting a few seconds to let Lambda write to CloudWatch Logs...\n",
    );
    await wait(10);

    const [logStream, logStreamErr] = await getLatestLogStreamForLambda({
      functionName: state.AutoConfirmHandlerName,
      region: state.stackRegion,
    });
    if (logStreamErr) {
      state.errors.push(logStreamErr);
      return;
    }

    console.log(
      `Getting some recent events from log stream "${logStream.logStreamName}"`,
    );
    const [logEvents, logEventsErr] = await getLogEvents({
      functionName: state.AutoConfirmHandlerName,
      region: state.stackRegion,
      eventCount: 10,
      logStreamName: logStream.logStreamName,
    });
    if (logEventsErr) {
      state.errors.push(logEventsErr);
      return;
    }

    console.log(logEvents.map((ev) => `\t${ev.message}`).join(""));
  },
  { skipWhen: skipWhenErrors },
);

const logSignInUser = new ScenarioOutput(
  "logSignInUser",
  (/** @type {State} */ state) => `Let's sign in as ${state.selectedUser}`,
  { skipWhen: skipWhenErrors },
);

const signInUser = new ScenarioAction(
  "signInUser",
  async (/** @type {State} */ state) => {
    const [response, err] = await signIn({
      region: state.stackRegion,
      clientId: state.UserPoolClientId,
      username: state.selectedUser,
      password: state.password,
    });

    if (err?.name === "PasswordResetRequiredException") {
      state.errors.push(new Error("Please reset your password."));
      return;
    }

    if (err) {
      state.errors.push(err);
      return;
    }

    state.token = response?.AuthenticationResult?.AccessToken;
  },
  { skipWhen: skipWhenErrors },
);

const logSignInUserComplete = new ScenarioOutput(
  "logSignInUserComplete",
  (/** @type {State} */ state) =>
    `Successfully signed in. Your access token starts with: ${state.token.slice(0, 11)}`,
  { skipWhen: skipWhenErrors },
);

const confirmDeleteSignedInUser = new ScenarioInput(
  "confirmDeleteSignedInUser",
  "Do you want to delete the currently signed in user?",
  { type: "confirm", skipWhen: skipWhenErrors },
);

const deleteSignedInUser = new ScenarioAction(
  "deleteSignedInUser",
  async (/** @type {State} */ state) => {
    const [_, err] = await deleteUser({
      region: state.stackRegion,
      accessToken: state.token,
    });

    if (err) {
      state.errors.push(err);
    }
  },
  {
    skipWhen: (/** @type {State} */ state) =>
      skipWhenErrors(state) || !state.confirmDeleteSignedInUser,
  },
);

const logErrors = new ScenarioOutput(
  "logErrors",
  (/** @type {State}*/ state) => {
    const errorList = state.errors
      .map((err) => ` - ${err.name}: ${err.message}`)
      .join("\n");
    return `Scenario errors found:\n${errorList}`;
  },
  {
    // Don't log errors when there aren't any!
    skipWhen: (/** @type {State} */ state) => state.errors.length === 0,
  },
);

export const AutoConfirm = (context) =>
  new Scenario(
    "AutoConfirm",
    [
      promptForStackName,
      promptForStackRegion,
      getStackOutputs,
      greeting,
      logPopulatingUsers,
      populateUsers,
      logPopulatingUsersComplete,
      logSetupSignUpTrigger,
      setupSignUpTrigger,
      logSetupSignUpTriggerComplete,
      selectUser,
      checkIfUserAlreadyExists,
      createPassword,
      logSignUpExistingUser,
      signUpExistingUser,
      logSignUpExistingUserComplete,
      logLambdaLogs,
      logSignInUser,
      signInUser,
      logSignInUserComplete,
      confirmDeleteSignedInUser,
      deleteSignedInUser,
      logCleanUpReminder,
      logErrors,
    ],
    context,
  );
```
這些是與其他案例共用的步驟。  

```
import {
  ScenarioAction,
  ScenarioInput,
  ScenarioOutput,
} from "@aws-doc-sdk-examples/lib/scenario/scenario.js";
import { getCfnOutputs } from "@aws-doc-sdk-examples/lib/sdk/cfn-outputs.js";

export const skipWhenErrors = (state) => state.errors.length > 0;

export const getStackOutputs = new ScenarioAction(
  "getStackOutputs",
  async (state) => {
    if (!state.stackName || !state.stackRegion) {
      state.errors.push(
        new Error(
          "No stack name or region provided. The stack name and \
region are required to fetch CFN outputs relevant to this example.",
        ),
      );
      return;
    }

    const outputs = await getCfnOutputs(state.stackName, state.stackRegion);
    Object.assign(state, outputs);
  },
);

export const promptForStackName = new ScenarioInput(
  "stackName",
  "Enter the name of the stack you deployed earlier.",
  { type: "input", default: "PoolsAndTriggersStack" },
);

export const promptForStackRegion = new ScenarioInput(
  "stackRegion",
  "Enter the region of the stack you deployed earlier.",
  { type: "input", default: "us-east-1" },
);

export const logCleanUpReminder = new ScenarioOutput(
  "logCleanUpReminder",
  "All done. Remember to run 'cdk destroy' to teardown the stack.",
  { skipWhen: skipWhenErrors },
);
```
具有 Lambda 函數之 `PreSignUp` 觸發條件的處理常式。  

```
import type { PreSignUpTriggerEvent, Handler } from "aws-lambda";
import type { UserRepository } from "./user-repository";
import { DynamoDBUserRepository } from "./user-repository";

export class PreSignUpHandler {
  private userRepository: UserRepository;

  constructor(userRepository: UserRepository) {
    this.userRepository = userRepository;
  }

  private isPreSignUpTriggerSource(event: PreSignUpTriggerEvent): boolean {
    return event.triggerSource === "PreSignUp_SignUp";
  }

  private getEventUserEmail(event: PreSignUpTriggerEvent): string {
    return event.request.userAttributes.email;
  }

  async handlePreSignUpTriggerEvent(
    event: PreSignUpTriggerEvent,
  ): Promise<PreSignUpTriggerEvent> {
    console.log(
      `Received presignup from ${event.triggerSource} for user '${event.userName}'`,
    );

    if (!this.isPreSignUpTriggerSource(event)) {
      return event;
    }

    const eventEmail = this.getEventUserEmail(event);
    console.log(`Looking up email ${eventEmail}.`);
    const storedUserInfo =
      await this.userRepository.getUserInfoByEmail(eventEmail);

    if (!storedUserInfo) {
      console.log(
        `Email ${eventEmail} not found. Email verification is required.`,
      );
      return event;
    }

    if (storedUserInfo.UserName !== event.userName) {
      console.log(
        `UserEmail ${eventEmail} found, but stored UserName '${storedUserInfo.UserName}' does not match supplied UserName '${event.userName}'. Verification is required.`,
      );
    } else {
      console.log(
        `UserEmail ${eventEmail} found with matching UserName ${storedUserInfo.UserName}. User is confirmed.`,
      );
      event.response.autoConfirmUser = true;
      event.response.autoVerifyEmail = true;
    }
    return event;
  }
}

const createPreSignUpHandler = (): PreSignUpHandler => {
  const tableName = process.env.TABLE_NAME;
  if (!tableName) {
    throw new Error("TABLE_NAME environment variable is not set");
  }

  const userRepository = new DynamoDBUserRepository(tableName);
  return new PreSignUpHandler(userRepository);
};

export const handler: Handler = async (event: PreSignUpTriggerEvent) => {
  const preSignUpHandler = createPreSignUpHandler();
  return preSignUpHandler.handlePreSignUpTriggerEvent(event);
};
```
CloudWatch Logs 動作的模組。  

```
import {
  CloudWatchLogsClient,
  GetLogEventsCommand,
  OrderBy,
  paginateDescribeLogStreams,
} from "@aws-sdk/client-cloudwatch-logs";

/**
 * Get the latest log stream for a Lambda function.
 * @param {{ functionName: string, region: string }} config
 * @returns {Promise<[import("@aws-sdk/client-cloudwatch-logs").LogStream | null, unknown]>}
 */
export const getLatestLogStreamForLambda = async ({ functionName, region }) => {
  try {
    const logGroupName = `/aws/lambda/${functionName}`;
    const cwlClient = new CloudWatchLogsClient({ region });
    const paginator = paginateDescribeLogStreams(
      { client: cwlClient },
      {
        descending: true,
        limit: 1,
        orderBy: OrderBy.LastEventTime,
        logGroupName,
      },
    );

    for await (const page of paginator) {
      return [page.logStreams[0], null];
    }
  } catch (err) {
    return [null, err];
  }
};

/**
 * Get the log events for a Lambda function's log stream.
 * @param {{
 *   functionName: string,
 *   logStreamName: string,
 *   eventCount: number,
 *   region: string
 * }} config
 * @returns {Promise<[import("@aws-sdk/client-cloudwatch-logs").OutputLogEvent[] | null, unknown]>}
 */
export const getLogEvents = async ({
  functionName,
  logStreamName,
  eventCount,
  region,
}) => {
  try {
    const cwlClient = new CloudWatchLogsClient({ region });
    const logGroupName = `/aws/lambda/${functionName}`;
    const response = await cwlClient.send(
      new GetLogEventsCommand({
        logStreamName: logStreamName,
        limit: eventCount,
        logGroupName: logGroupName,
      }),
    );

    return [response.events, null];
  } catch (err) {
    return [null, err];
  }
};
```
Amazon Cognito 動作的模組。  

```
import {
  AdminGetUserCommand,
  CognitoIdentityProviderClient,
  DeleteUserCommand,
  InitiateAuthCommand,
  SignUpCommand,
  UpdateUserPoolCommand,
} from "@aws-sdk/client-cognito-identity-provider";

/**
 * Connect a Lambda function to the PreSignUp trigger for a Cognito user pool
 * @param {{ region: string, userPoolId: string, handlerArn: string }} config
 * @returns {Promise<[import("@aws-sdk/client-cognito-identity-provider").UpdateUserPoolCommandOutput | null, unknown]>}
 */
export const addPreSignUpHandler = async ({
  region,
  userPoolId,
  handlerArn,
}) => {
  try {
    const cognitoClient = new CognitoIdentityProviderClient({
      region,
    });

    const command = new UpdateUserPoolCommand({
      UserPoolId: userPoolId,
      LambdaConfig: {
        PreSignUp: handlerArn,
      },
    });

    const response = await cognitoClient.send(command);
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};

/**
 * Attempt to register a user to a user pool with a given username and password.
 * @param {{
 *   region: string,
 *   userPoolClientId: string,
 *   username: string,
 *   email: string,
 *   password: string
 * }} config
 * @returns {Promise<[import("@aws-sdk/client-cognito-identity-provider").SignUpCommandOutput | null, unknown]>}
 */
export const signUpUser = async ({
  region,
  userPoolClientId,
  username,
  email,
  password,
}) => {
  try {
    const cognitoClient = new CognitoIdentityProviderClient({
      region,
    });

    const response = await cognitoClient.send(
      new SignUpCommand({
        ClientId: userPoolClientId,
        Username: username,
        Password: password,
        UserAttributes: [{ Name: "email", Value: email }],
      }),
    );
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};

/**
 * Sign in a user to Amazon Cognito using a username and password authentication flow.
 * @param {{ region: string, clientId: string, username: string, password: string }} config
 * @returns {Promise<[import("@aws-sdk/client-cognito-identity-provider").InitiateAuthCommandOutput | null, unknown]>}
 */
export const signIn = async ({ region, clientId, username, password }) => {
  try {
    const cognitoClient = new CognitoIdentityProviderClient({ region });
    const response = await cognitoClient.send(
      new InitiateAuthCommand({
        AuthFlow: "USER_PASSWORD_AUTH",
        ClientId: clientId,
        AuthParameters: { USERNAME: username, PASSWORD: password },
      }),
    );
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};

/**
 * Retrieve an existing user from a user pool.
 * @param {{ region: string, userPoolId: string, username: string }} config
 * @returns {Promise<[import("@aws-sdk/client-cognito-identity-provider").AdminGetUserCommandOutput | null, unknown]>}
 */
export const getUser = async ({ region, userPoolId, username }) => {
  try {
    const cognitoClient = new CognitoIdentityProviderClient({ region });
    const response = await cognitoClient.send(
      new AdminGetUserCommand({
        UserPoolId: userPoolId,
        Username: username,
      }),
    );
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};

/**
 * Delete the signed-in user. Useful for allowing a user to delete their
 * own profile.
 * @param {{ region: string, accessToken: string }} config
 * @returns {Promise<[import("@aws-sdk/client-cognito-identity-provider").DeleteUserCommandOutput | null, unknown]>}
 */
export const deleteUser = async ({ region, accessToken }) => {
  try {
    const client = new CognitoIdentityProviderClient({ region });
    const response = await client.send(
      new DeleteUserCommand({ AccessToken: accessToken }),
    );
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};
```
DynamoDB 動作的模組。  

```
import { DynamoDBClient } from "@aws-sdk/client-dynamodb";
import {
  BatchWriteCommand,
  DynamoDBDocumentClient,
} from "@aws-sdk/lib-dynamodb";

/**
 * Populate a DynamoDB table with provide items.
 * @param {{ region: string, tableName: string, items: Record<string, unknown>[] }} config
 * @returns {Promise<[import("@aws-sdk/lib-dynamodb").BatchWriteCommandOutput | null, unknown]>}
 */
export const populateTable = async ({ region, tableName, items }) => {
  try {
    const ddbClient = new DynamoDBClient({ region });
    const docClient = DynamoDBDocumentClient.from(ddbClient);
    const response = await docClient.send(
      new BatchWriteCommand({
        RequestItems: {
          [tableName]: items.map((item) => ({
            PutRequest: {
              Item: item,
            },
          })),
        },
      }),
    );
    return [response, null];
  } catch (err) {
    return [null, err];
  }
};
```
+ 如需 API 詳細資訊，請參閱《*適用於 JavaScript 的 AWS SDK API 參考*》中的下列主題。
  + [DeleteUser](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cognito-identity-provider/command/DeleteUserCommand)
  + [InitiateAuth](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cognito-identity-provider/command/InitiateAuthCommand)
  + [SignUp](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cognito-identity-provider/command/SignUpCommand)
  + [UpdateUserPool](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cognito-identity-provider/command/UpdateUserPoolCommand)

### 建立無伺服器應用程式來管理相片
<a name="cross_PAM_javascript_3_topic"></a>

下列程式碼範例示範如何建立無伺服器應用程式，讓使用者以標籤管理相片。

**適用於 JavaScript (v3) 的 SDK**  
 顯示如何開發照片資產管理應用程式，以便使用 Amazon Rekognition 偵測圖片中的標籤，並將其儲存以供日後擷取。  
如需完整的原始碼和如何設定及執行的指示，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/photo-asset-manager) 上的完整範例。  
如要深入探索此範例的來源，請參閱 [AWS  社群](https://community.aws/posts/cloud-journeys/01-serverless-image-recognition-app)上的文章。  

**此範例中使用的服務**
+ API Gateway
+ DynamoDB
+ Lambda
+ Amazon Rekognition
+ Amazon S3
+ Amazon SNS

### 建立應用程式以分析客戶意見回饋
<a name="cross_FSA_javascript_3_topic"></a>

下列程式碼範例會示範如何建立可分析客戶評論卡、從其原始語言進行翻譯、判斷對方情緒，以及透過翻譯後的文字產生音訊檔案的應用程式。

**適用於 JavaScript (v3) 的 SDK**  
 此範例應用程式會分析和存儲客戶的意見回饋卡。具體來說，它滿足了紐約市一家虛構飯店的需求。飯店以實體評論卡的形式收到賓客以各種語言撰寫的意見回饋。這些意見回饋透過 Web 用戶端上傳至應用程式。評論卡的影像上傳後，系統會執行下列步驟：  
+ 文字內容是使用 Amazon Textract 從影像中擷取。
+ Amazon Comprehend 會決定擷取文字及其用語的情感。
+ 擷取的文字內容會使用 Amazon Translate 翻譯成英文。
+ Amazon Polly 會使用擷取的文字內容合成音訊檔案。
 完整的應用程式可透過  AWS CDK 部署。如需原始程式碼和部署的說明，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/feedback-sentiment-analyzer) 中的專案。以下摘錄顯示如何在 Lambda 函數內 適用於 JavaScript 的 AWS SDK 使用 。  

```
import {
  ComprehendClient,
  DetectDominantLanguageCommand,
  DetectSentimentCommand,
} from "@aws-sdk/client-comprehend";

/**
 * Determine the language and sentiment of the extracted text.
 *
 * @param {{ source_text: string}} extractTextOutput
 */
export const handler = async (extractTextOutput) => {
  const comprehendClient = new ComprehendClient({});

  const detectDominantLanguageCommand = new DetectDominantLanguageCommand({
    Text: extractTextOutput.source_text,
  });

  // The source language is required for sentiment analysis and
  // translation in the next step.
  const { Languages } = await comprehendClient.send(
    detectDominantLanguageCommand,
  );

  const languageCode = Languages[0].LanguageCode;

  const detectSentimentCommand = new DetectSentimentCommand({
    Text: extractTextOutput.source_text,
    LanguageCode: languageCode,
  });

  const { Sentiment } = await comprehendClient.send(detectSentimentCommand);

  return {
    sentiment: Sentiment,
    language_code: languageCode,
  };
};
```

```
import {
  DetectDocumentTextCommand,
  TextractClient,
} from "@aws-sdk/client-textract";

/**
 * Fetch the S3 object from the event and analyze it using Amazon Textract.
 *
 * @param {import("@types/aws-lambda").EventBridgeEvent<"Object Created">} eventBridgeS3Event
 */
export const handler = async (eventBridgeS3Event) => {
  const textractClient = new TextractClient();

  const detectDocumentTextCommand = new DetectDocumentTextCommand({
    Document: {
      S3Object: {
        Bucket: eventBridgeS3Event.bucket,
        Name: eventBridgeS3Event.object,
      },
    },
  });

  // Textract returns a list of blocks. A block can be a line, a page, word, etc.
  // Each block also contains geometry of the detected text.
  // For more information on the Block type, see https://docs.aws.amazon.com/textract/latest/dg/API_Block.html.
  const { Blocks } = await textractClient.send(detectDocumentTextCommand);

  // For the purpose of this example, we are only interested in words.
  const extractedWords = Blocks.filter((b) => b.BlockType === "WORD").map(
    (b) => b.Text,
  );

  return extractedWords.join(" ");
};
```

```
import { PollyClient, SynthesizeSpeechCommand } from "@aws-sdk/client-polly";
import { S3Client } from "@aws-sdk/client-s3";
import { Upload } from "@aws-sdk/lib-storage";

/**
 * Synthesize an audio file from text.
 *
 * @param {{ bucket: string, translated_text: string, object: string}} sourceDestinationConfig
 */
export const handler = async (sourceDestinationConfig) => {
  const pollyClient = new PollyClient({});

  const synthesizeSpeechCommand = new SynthesizeSpeechCommand({
    Engine: "neural",
    Text: sourceDestinationConfig.translated_text,
    VoiceId: "Ruth",
    OutputFormat: "mp3",
  });

  const { AudioStream } = await pollyClient.send(synthesizeSpeechCommand);

  const audioKey = `${sourceDestinationConfig.object}.mp3`;

  // Store the audio file in S3.
  const s3Client = new S3Client();
  const upload = new Upload({
    client: s3Client,
    params: {
      Bucket: sourceDestinationConfig.bucket,
      Key: audioKey,
      Body: AudioStream,
      ContentType: "audio/mp3",
    },
  });

  await upload.done();
  return audioKey;
};
```

```
import {
  TranslateClient,
  TranslateTextCommand,
} from "@aws-sdk/client-translate";

/**
 * Translate the extracted text to English.
 *
 * @param {{ extracted_text: string, source_language_code: string}} textAndSourceLanguage
 */
export const handler = async (textAndSourceLanguage) => {
  const translateClient = new TranslateClient({});

  const translateCommand = new TranslateTextCommand({
    SourceLanguageCode: textAndSourceLanguage.source_language_code,
    TargetLanguageCode: "en",
    Text: textAndSourceLanguage.extracted_text,
  });

  const { TranslatedText } = await translateClient.send(translateCommand);

  return { translated_text: TranslatedText };
};
```

**此範例中使用的服務**
+ Amazon Comprehend
+ Lambda
+ Amazon Polly
+ Amazon Textract
+ Amazon Translate

### 從瀏覽器調用 Lambda 函式
<a name="cross_LambdaForBrowser_javascript_3_topic"></a>

下列程式碼範例示範如何從瀏覽器叫用 AWS Lambda 函數。

**適用於 JavaScript (v3) 的 SDK**  
 您可以建立瀏覽器型應用程式，該應用程式使用 AWS Lambda 函數更新具有使用者選擇的 Amazon DynamoDB 資料表。此應用程式使用 適用於 JavaScript 的 AWS SDK v3。  
 如需完整的原始碼和如何設定及執行的指示，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/lambda-for-browser) 上的完整範例。  

**此範例中使用的服務**
+ DynamoDB
+ Lambda

### 使用 API Gateway 來調用 Lambda 函式
<a name="cross_LambdaAPIGateway_javascript_3_topic"></a>

下列程式碼範例示範如何建立 Amazon API Gateway 調用的 AWS Lambda 函數。

**適用於 JavaScript (v3) 的 SDK**  
 示範如何使用 Lambda JavaScript 執行時間 API 建立 AWS Lambda 函數。此範例會叫用不同的 AWS 服務來執行特定的使用案例。此範例示範如何建立 Amazon API Gateway 調用的 Lambda 函式，該函數會掃描 Amazon DynamoDB 資料表中的工作週年紀念日，並使用 Amazon Simple Notification Service (Amazon SNS) 傳送文字訊息給您的員工，在他們的週年紀念日向他們道賀。  
 如需完整的原始碼和如何設定及執行的指示，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/lambda-api-gateway) 上的完整範例。  
此範例也可在 [適用於 JavaScript 的 AWS SDK v3 開發人員指南](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/api-gateway-invoking-lambda-example.html)中取得。  

**此範例中使用的服務**
+ API Gateway
+ DynamoDB
+ Lambda
+ Amazon SNS

### 使用排程事件來調用 Lambda 函式
<a name="cross_LambdaScheduledEvents_javascript_3_topic"></a>

下列程式碼範例示範如何建立由 Amazon EventBridge 排程事件呼叫的 AWS Lambda 函數。

**適用於 JavaScript (v3) 的 SDK**  
 顯示如何建立叫用 AWS Lambda 函數的 Amazon EventBridge 排程事件。將 EventBridge 設定為在調用 Lambda 函式時使用 Cron 表達式來進行排程。在此範例中，您會使用 Lambda JavaScript 執行時期 API 建立 Lambda 函式。此範例會叫用不同的 AWS 服務來執行特定的使用案例。此範例示範如何建立應用程式，將行動裝置文字訊息傳送給員工，在他們的週年紀念日向他們道賀。  
 如需完整的原始碼和如何設定及執行的指示，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/lambda-scheduled-events) 上的完整範例。  
此範例也可在 [適用於 JavaScript 的 AWS SDK v3 開發人員指南](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/scheduled-events-invoking-lambda-example.html)中取得。  

**此範例中使用的服務**
+ CloudWatch Logs
+ DynamoDB
+ EventBridge
+ Lambda
+ Amazon SNS

## 無伺服器範例
<a name="serverless_examples"></a>

### 連線至 Lambda 函數中的 Amazon RDS 資料庫
<a name="serverless_connect_RDS_Lambda_javascript_3_topic"></a>

以下程式碼範例示範如何實作連線至 RDS 資料庫的 Lambda 函式。該函數會提出簡單的資料庫請求並傳回結果。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/lambda-function-connect-rds-iam)儲存庫中設定和執行。
使用 JavaScript 連線至 Lambda 函數中的 Amazon RDS 資料庫。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
/* 
Node.js code here.
*/
// ES6+ example
import { Signer } from "@aws-sdk/rds-signer";
import mysql from 'mysql2/promise';

async function createAuthToken() {
  // Define connection authentication parameters
  const dbinfo = {

    hostname: process.env.ProxyHostName,
    port: process.env.Port,
    username: process.env.DBUserName,
    region: process.env.AWS_REGION,

  }

  // Create RDS Signer object
  const signer = new Signer(dbinfo);

  // Request authorization token from RDS, specifying the username
  const token = await signer.getAuthToken();
  return token;
}

async function dbOps() {

  // Obtain auth token
  const token = await createAuthToken();
  // Define connection configuration
  let connectionConfig = {
    host: process.env.ProxyHostName,
    user: process.env.DBUserName,
    password: token,
    database: process.env.DBName,
    ssl: 'Amazon RDS'
  }
  // Create the connection to the DB
  const conn = await mysql.createConnection(connectionConfig);
  // Obtain the result of the query
  const [res,] = await conn.execute('select ?+? as sum', [3, 2]);
  return res;

}

export const handler = async (event) => {
  // Execute database flow
  const result = await dbOps();
  // Return result
  return {
    statusCode: 200,
    body: JSON.stringify("The selected sum is: " + result[0].sum)
  }
};
```
使用 TypeScript 連線至 Lambda 函數中的 Amazon RDS 資料庫。  

```
import { Signer } from "@aws-sdk/rds-signer";
import mysql from 'mysql2/promise';

// RDS settings
// Using '!' (non-null assertion operator) to tell the TypeScript compiler that the DB settings are not null or undefined,
const proxy_host_name = process.env.PROXY_HOST_NAME!
const port = parseInt(process.env.PORT!)
const db_name = process.env.DB_NAME!
const db_user_name = process.env.DB_USER_NAME!
const aws_region = process.env.AWS_REGION!


async function createAuthToken(): Promise<string> {

    // Create RDS Signer object
    const signer = new Signer({
        hostname: proxy_host_name,
        port: port,
        region: aws_region,
        username: db_user_name
    });

    // Request authorization token from RDS, specifying the username
    const token = await signer.getAuthToken();
    return token;
}

async function dbOps(): Promise<mysql.QueryResult | undefined> {
    try {
        // Obtain auth token
        const token = await createAuthToken();
        const conn = await mysql.createConnection({
            host: proxy_host_name,
            user: db_user_name,
            password: token,
            database: db_name,
            ssl: 'Amazon RDS' // Ensure you have the CA bundle for SSL connection
        });
        const [rows, fields] = await conn.execute('SELECT ? + ? AS sum', [3, 2]);
        console.log('result:', rows);
        return rows;
    }
    catch (err) {
        console.log(err);
    }
}

export const lambdaHandler = async (event: any): Promise<{ statusCode: number; body: string }> => {
    // Execute database flow
    const result = await dbOps();

    // Return error is result is undefined
    if (result == undefined)
        return {
            statusCode: 500,
            body: JSON.stringify(`Error with connection to DB host`)
        }

    // Return result
    return {
        statusCode: 200,
        body: JSON.stringify(`The selected sum is: ${result[0].sum}`)
    };
};
```

### 使用 Kinesis 觸發條件調用 Lambda 函數
<a name="serverless_Kinesis_Lambda_javascript_3_topic"></a>

以下程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 Kinesis 串流的記錄來接收所觸發的事件。此函數會擷取 Kinesis 承載、從 Base64 解碼，並記錄記錄內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/blob/main/integration-kinesis-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來使用 Kinesis 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
exports.handler = async (event, context) => {
  for (const record of event.Records) {
    try {
      console.log(`Processed Kinesis Event - EventID: ${record.eventID}`);
      const recordData = await getRecordDataAsync(record.kinesis);
      console.log(`Record Data: ${recordData}`);
      // TODO: Do interesting work based on the new data
    } catch (err) {
      console.error(`An error occurred ${err}`);
      throw err;
    }
  }
  console.log(`Successfully processed ${event.Records.length} records.`);
};

async function getRecordDataAsync(payload) {
  var data = Buffer.from(payload.data, "base64").toString("utf-8");
  await Promise.resolve(1); //Placeholder for actual async work
  return data;
}
```
使用 TypeScript 搭配 Lambda 來使用 Kinesis 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import {
  KinesisStreamEvent,
  Context,
  KinesisStreamHandler,
  KinesisStreamRecordPayload,
} from "aws-lambda";
import { Buffer } from "buffer";
import { Logger } from "@aws-lambda-powertools/logger";

const logger = new Logger({
  logLevel: "INFO",
  serviceName: "kinesis-stream-handler-sample",
});

export const functionHandler: KinesisStreamHandler = async (
  event: KinesisStreamEvent,
  context: Context
): Promise<void> => {
  for (const record of event.Records) {
    try {
      logger.info(`Processed Kinesis Event - EventID: ${record.eventID}`);
      const recordData = await getRecordDataAsync(record.kinesis);
      logger.info(`Record Data: ${recordData}`);
      // TODO: Do interesting work based on the new data
    } catch (err) {
      logger.error(`An error occurred ${err}`);
      throw err;
    }
    logger.info(`Successfully processed ${event.Records.length} records.`);
  }
};

async function getRecordDataAsync(
  payload: KinesisStreamRecordPayload
): Promise<string> {
  var data = Buffer.from(payload.data, "base64").toString("utf-8");
  await Promise.resolve(1); //Placeholder for actual async work
  return data;
}
```

### 使用 DynamoDB 觸發條件調用 Lambda 函式
<a name="serverless_DynamoDB_Lambda_javascript_3_topic"></a>

以下程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 DynamoDB 串流的記錄來接收所觸發的事件。函數會擷取 DynamoDB 承載並記下記錄內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-ddb-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來使用 DynamoDB 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
exports.handler = async (event, context) => {
    console.log(JSON.stringify(event, null, 2));
    event.Records.forEach(record => {
        logDynamoDBRecord(record);
    });
};

const logDynamoDBRecord = (record) => {
    console.log(record.eventID);
    console.log(record.eventName);
    console.log(`DynamoDB Record: ${JSON.stringify(record.dynamodb)}`);
};
```
使用 TypeScript 搭配 Lambda 來使用 DynamoDB 事件。  

```
export const handler = async (event, context) => {
    console.log(JSON.stringify(event, null, 2));
    event.Records.forEach(record => {
        logDynamoDBRecord(record);
    });
}
const logDynamoDBRecord = (record) => {
    console.log(record.eventID);
    console.log(record.eventName);
    console.log(`DynamoDB Record: ${JSON.stringify(record.dynamodb)}`);
};
```

### 使用 Amazon DocumentDB 觸發條件調用 Lambda 函數
<a name="serverless_DocumentDB_Lambda_javascript_3_topic"></a>

以下程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 DocumentDB 變更串流的記錄來接收所觸發的事件。函數會擷取 DocumentDB 承載並記下記錄內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-docdb-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 使用 Amazon DocumentDB 事件。  

```
console.log('Loading function');
exports.handler = async (event, context) => {
    event.events.forEach(record => {
        logDocumentDBEvent(record);
    });
    return 'OK';
};

const logDocumentDBEvent = (record) => {
    console.log('Operation type: ' + record.event.operationType);
    console.log('db: ' + record.event.ns.db);
    console.log('collection: ' + record.event.ns.coll);
    console.log('Full document:', JSON.stringify(record.event.fullDocument, null, 2));
};
```
使用 TypeScript 搭配 Lambda 使用 Amazon DocumentDB 事件  

```
import { DocumentDBEventRecord, DocumentDBEventSubscriptionContext } from 'aws-lambda';

console.log('Loading function');

export const handler = async (
  event: DocumentDBEventSubscriptionContext,
  context: any
): Promise<string> => {
  event.events.forEach((record: DocumentDBEventRecord) => {
    logDocumentDBEvent(record);
  });
  return 'OK';
};

const logDocumentDBEvent = (record: DocumentDBEventRecord): void => {
  console.log('Operation type: ' + record.event.operationType);
  console.log('db: ' + record.event.ns.db);
  console.log('collection: ' + record.event.ns.coll);
  console.log('Full document:', JSON.stringify(record.event.fullDocument, null, 2));
};
```

### 使用 Amazon MSK 觸發條件調用 Lambda 函數
<a name="serverless_MSK_Lambda_javascript_3_topic"></a>

以下程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 Amazon MSK 叢集的記錄來接收所觸發的事件。函數會擷取 MSK 承載並記下記錄內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-msk-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來取用 Amazon MSK 事件。  

```
exports.handler = async (event) => {
    // Iterate through keys
    for (let key in event.records) {
      console.log('Key: ', key)
      // Iterate through records
      event.records[key].map((record) => {
        console.log('Record: ', record)
        // Decode base64
        const msg = Buffer.from(record.value, 'base64').toString()
        console.log('Message:', msg)
      }) 
    }
}
```
搭配 Lambda 使用 TypeScript 來取用 Amazon MSK 事件。  

```
import { MSKEvent, Context } from "aws-lambda";
import { Buffer } from "buffer";
import { Logger } from "@aws-lambda-powertools/logger";

const logger = new Logger({
  logLevel: "INFO",
  serviceName: "msk-handler-sample",
});

export const handler = async (
  event: MSKEvent,
  context: Context
): Promise<void> => {
  for (const [topic, topicRecords] of Object.entries(event.records)) {
    logger.info(`Processing key: ${topic}`);

    // Process each record in the partition
    for (const record of topicRecords) {
      try {
        // Decode the message value from base64
        const decodedMessage = Buffer.from(record.value, 'base64').toString();

        logger.info({
          message: decodedMessage
        });
      }
      catch (error) {
        logger.error('Error processing event', { error });
        throw error;
      }
    };
  }
}
```

### 使用 Amazon S3 觸發條件調用 Lambda 函數
<a name="serverless_S3_Lambda_javascript_3_topic"></a>

下列程式碼範例示範如何實作 Lambda 函式，該函式接收透過上傳物件至 S3 儲存貯體時所觸發的事件。此函數會從事件參數擷取 S3 儲存貯體名稱和物件金鑰，並呼叫 Amazon S3 API 以擷取和記錄物件的內容類型。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-s3-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來使用 S3 事件。  

```
import { S3Client, HeadObjectCommand } from "@aws-sdk/client-s3";

const client = new S3Client();

export const handler = async (event, context) => {

    // Get the object from the event and show its content type
    const bucket = event.Records[0].s3.bucket.name;
    const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));

    try {
        const { ContentType } = await client.send(new HeadObjectCommand({
            Bucket: bucket,
            Key: key,
        }));

        console.log('CONTENT TYPE:', ContentType);
        return ContentType;

    } catch (err) {
        console.log(err);
        const message = `Error getting object ${key} from bucket ${bucket}. Make sure they exist and your bucket is in the same region as this function.`;
        console.log(message);
        throw new Error(message);
    }
};
```
使用 TypeScript 搭配 Lambda 來使用 S3 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import { S3Event } from 'aws-lambda';
import { S3Client, HeadObjectCommand } from '@aws-sdk/client-s3';

const s3 = new S3Client({ region: process.env.AWS_REGION });

export const handler = async (event: S3Event): Promise<string | undefined> => {
  // Get the object from the event and show its content type
  const bucket = event.Records[0].s3.bucket.name;
  const key = decodeURIComponent(event.Records[0].s3.object.key.replace(/\+/g, ' '));
  const params = {
    Bucket: bucket,
    Key: key,
  };
  try {
    const { ContentType } = await s3.send(new HeadObjectCommand(params));
    console.log('CONTENT TYPE:', ContentType);
    return ContentType;
  } catch (err) {
    console.log(err);
    const message = `Error getting object ${key} from bucket ${bucket}. Make sure they exist and your bucket is in the same region as this function.`;
    console.log(message);
    throw new Error(message);
  }
};
```

### 使用 Amazon SNS 觸發條件調用 Lambda 函數
<a name="serverless_SNS_Lambda_javascript_3_topic"></a>

下列程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 SNS 主題的訊息來接收所觸發的事件。函數會從事件參數擷取訊息，並記錄每一則訊息的內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/blob/main/integration-sns-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來使用 SNS 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
exports.handler = async (event, context) => {
  for (const record of event.Records) {
    await processMessageAsync(record);
  }
  console.info("done");
};

async function processMessageAsync(record) {
  try {
    const message = JSON.stringify(record.Sns.Message);
    console.log(`Processed message ${message}`);
    await Promise.resolve(1); //Placeholder for actual async work
  } catch (err) {
    console.error("An error occurred");
    throw err;
  }
}
```
使用 TypeScript 搭配 Lambda 來使用 SNS 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import { SNSEvent, Context, SNSHandler, SNSEventRecord } from "aws-lambda";

export const functionHandler: SNSHandler = async (
  event: SNSEvent,
  context: Context
): Promise<void> => {
  for (const record of event.Records) {
    await processMessageAsync(record);
  }
  console.info("done");
};

async function processMessageAsync(record: SNSEventRecord): Promise<any> {
  try {
    const message: string = JSON.stringify(record.Sns.Message);
    console.log(`Processed message ${message}`);
    await Promise.resolve(1); //Placeholder for actual async work
  } catch (err) {
    console.error("An error occurred");
    throw err;
  }
}
```

### 使用 Amazon SQS 觸發條件調用 Lambda 函數
<a name="serverless_SQS_Lambda_javascript_3_topic"></a>

下列程式碼範例示範如何實作 Lambda 函式，該函式會透過接收 SQS 佇列的訊息來接收所觸發的事件。函數會從事件參數擷取訊息，並記錄每一則訊息的內容。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/blob/main/integration-sqs-to-lambda)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 來使用 SQS 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
exports.handler = async (event, context) => {
  for (const message of event.Records) {
    await processMessageAsync(message);
  }
  console.info("done");
};

async function processMessageAsync(message) {
  try {
    console.log(`Processed message ${message.body}`);
    // TODO: Do interesting work based on the new message
    await Promise.resolve(1); //Placeholder for actual async work
  } catch (err) {
    console.error("An error occurred");
    throw err;
  }
}
```
使用 TypeScript 搭配 Lambda 來使用 SQS 事件。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import { SQSEvent, Context, SQSHandler, SQSRecord } from "aws-lambda";

export const functionHandler: SQSHandler = async (
  event: SQSEvent,
  context: Context
): Promise<void> => {
  for (const message of event.Records) {
    await processMessageAsync(message);
  }
  console.info("done");
};

async function processMessageAsync(message: SQSRecord): Promise<any> {
  try {
    console.log(`Processed message ${message.body}`);
    // TODO: Do interesting work based on the new message
    await Promise.resolve(1); //Placeholder for actual async work
  } catch (err) {
    console.error("An error occurred");
    throw err;
  }
}
```

### 使用 Kinesis 觸發條件報告 Lambda 函數的批次項目失敗
<a name="serverless_Kinesis_Lambda_batch_item_failures_javascript_3_topic"></a>

下列程式碼範例示範如何針對接收來自 Kinesis 串流之事件的 Lambda 函式，實作部分批次回應。此函數會在回應中報告批次項目失敗，指示 Lambda 稍後重試這些訊息。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/blob/main/integration-kinesis-to-lambda-with-batch-item-handling)儲存庫中設定和執行。
使用 Javascript 搭配 Lambda 報告 Kinesis 批次項目失敗。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
exports.handler = async (event, context) => {
  for (const record of event.Records) {
    try {
      console.log(`Processed Kinesis Event - EventID: ${record.eventID}`);
      const recordData = await getRecordDataAsync(record.kinesis);
      console.log(`Record Data: ${recordData}`);
      // TODO: Do interesting work based on the new data
    } catch (err) {
      console.error(`An error occurred ${err}`);
      /* Since we are working with streams, we can return the failed item immediately.
            Lambda will immediately begin to retry processing from this failed item onwards. */
      return {
        batchItemFailures: [{ itemIdentifier: record.kinesis.sequenceNumber }],
      };
    }
  }
  console.log(`Successfully processed ${event.Records.length} records.`);
  return { batchItemFailures: [] };
};

async function getRecordDataAsync(payload) {
  var data = Buffer.from(payload.data, "base64").toString("utf-8");
  await Promise.resolve(1); //Placeholder for actual async work
  return data;
}
```
使用 TypeScript 搭配 Lambda 報告 Kinesis 批次項目失敗。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import {
  KinesisStreamEvent,
  Context,
  KinesisStreamHandler,
  KinesisStreamRecordPayload,
  KinesisStreamBatchResponse,
} from "aws-lambda";
import { Buffer } from "buffer";
import { Logger } from "@aws-lambda-powertools/logger";

const logger = new Logger({
  logLevel: "INFO",
  serviceName: "kinesis-stream-handler-sample",
});

export const functionHandler: KinesisStreamHandler = async (
  event: KinesisStreamEvent,
  context: Context
): Promise<KinesisStreamBatchResponse> => {
  for (const record of event.Records) {
    try {
      logger.info(`Processed Kinesis Event - EventID: ${record.eventID}`);
      const recordData = await getRecordDataAsync(record.kinesis);
      logger.info(`Record Data: ${recordData}`);
      // TODO: Do interesting work based on the new data
    } catch (err) {
      logger.error(`An error occurred ${err}`);
      /* Since we are working with streams, we can return the failed item immediately.
            Lambda will immediately begin to retry processing from this failed item onwards. */
      return {
        batchItemFailures: [{ itemIdentifier: record.kinesis.sequenceNumber }],
      };
    }
  }
  logger.info(`Successfully processed ${event.Records.length} records.`);
  return { batchItemFailures: [] };
};

async function getRecordDataAsync(
  payload: KinesisStreamRecordPayload
): Promise<string> {
  var data = Buffer.from(payload.data, "base64").toString("utf-8");
  await Promise.resolve(1); //Placeholder for actual async work
  return data;
}
```

### 使用 DynamoDB 觸發條件報告 Lambda 函式的批次項目失敗
<a name="serverless_DynamoDB_Lambda_batch_item_failures_javascript_3_topic"></a>

下列程式碼範例示範如何針對接收來自 DynamoDB 串流之事件的 Lambda 函式，實作部分批次回應。此函數會在回應中報告批次項目失敗，指示 Lambda 稍後重試這些訊息。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/integration-ddb-to-lambda-with-batch-item-handling)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 報告 DynamoDB 批次項目失敗。  

```
export const handler = async (event) => {
  const records = event.Records;
  let curRecordSequenceNumber = "";

  for (const record of records) {
    try {
      // Process your record
      curRecordSequenceNumber = record.dynamodb.SequenceNumber;
    } catch (e) {
      // Return failed record's sequence number
      return { batchItemFailures: [{ itemIdentifier: curRecordSequenceNumber }] };
    }
  }

  return { batchItemFailures: [] };
};
```
使用 TypeScript 搭配 Lambda 報告 DynamoDB 批次項目失敗。  

```
import {
  DynamoDBBatchResponse,
  DynamoDBBatchItemFailure,
  DynamoDBStreamEvent,
} from "aws-lambda";

export const handler = async (
  event: DynamoDBStreamEvent
): Promise<DynamoDBBatchResponse> => {
  const batchItemFailures: DynamoDBBatchItemFailure[] = [];
  let curRecordSequenceNumber;

  for (const record of event.Records) {
    curRecordSequenceNumber = record.dynamodb?.SequenceNumber;

    if (curRecordSequenceNumber) {
      batchItemFailures.push({
        itemIdentifier: curRecordSequenceNumber,
      });
    }
  }

  return { batchItemFailures: batchItemFailures };
};
```

### 使用 Amazon SQS 觸發條件報告 Lambda 函數的批次項目失敗
<a name="serverless_SQS_Lambda_batch_item_failures_javascript_3_topic"></a>

下列程式碼範例示範如何為接收從 SQS 佇列接收事件的 Lambda 函式，實作部分批次回應。此函數會在回應中報告批次項目失敗，指示 Lambda 稍後重試這些訊息。

**適用於 JavaScript (v3) 的 SDK**  
 GitHub 上提供更多範例。尋找完整範例，並了解如何在[無伺服器範例](https://github.com/aws-samples/serverless-snippets/tree/main/lambda-function-sqs-report-batch-item-failures)儲存庫中設定和執行。
使用 JavaScript 搭配 Lambda 報告 SQS 批次項目失敗。  

```
// Node.js 20.x Lambda runtime, AWS SDK for Javascript V3
export const handler = async (event, context) => {
    const batchItemFailures = [];
    for (const record of event.Records) {
        try {
            await processMessageAsync(record, context);
        } catch (error) {
            batchItemFailures.push({ itemIdentifier: record.messageId });
        }
    }
    return { batchItemFailures };
};

async function processMessageAsync(record, context) {
    if (record.body && record.body.includes("error")) {
        throw new Error("There is an error in the SQS Message.");
    }
    console.log(`Processed message: ${record.body}`);
}
```
使用 TypeScript 搭配 Lambda 報告 SQS 批次項目失敗。  

```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import { SQSEvent, SQSBatchResponse, Context, SQSBatchItemFailure, SQSRecord } from 'aws-lambda';

export const handler = async (event: SQSEvent, context: Context): Promise<SQSBatchResponse> => {
    const batchItemFailures: SQSBatchItemFailure[] = [];

    for (const record of event.Records) {
        try {
            await processMessageAsync(record);
        } catch (error) {
            batchItemFailures.push({ itemIdentifier: record.messageId });
        }
    }

    return {batchItemFailures: batchItemFailures};
};

async function processMessageAsync(record: SQSRecord): Promise<void> {
    if (record.body && record.body.includes("error")) {
        throw new Error('There is an error in the SQS Message.');
    }
    console.log(`Processed message ${record.body}`);
}
```