AWS STS examples using SDK for JavaScript (v3)

Create the client.

import { STSClient } from "@aws-sdk/client-sts";
// Set the AWS Region.
const REGION = "us-east-1";
// Create an AWS STS service client object.
export const client = new STSClient({ region: REGION });

Assume the IAM role.

import { AssumeRoleCommand } from "@aws-sdk/client-sts";

import { client } from "../libs/client.js";

export const main = async () => {
  try {
    // Returns a set of temporary security credentials that you can use to
    // access Amazon Web Services resources that you might not normally
    // have access to.
    const command = new AssumeRoleCommand({
      // The Amazon Resource Name (ARN) of the role to assume.
      RoleArn: "ROLE_ARN",
      // An identifier for the assumed role session.
      RoleSessionName: "session1",
      // The duration, in seconds, of the role session. The value specified
      // can range from 900 seconds (15 minutes) up to the maximum session
      // duration set for the role.
      DurationSeconds: 900,
    });
    const response = await client.send(command);
    console.log(response);
  } catch (err) {
    console.error(err);
  }
};