# FunctionRuntime

The function's runtime environment version.

- Source: [`aws-cloudfront/lib/function.ts`](https://github.com/aws/aws-cdk/blob/v2.275.0/packages/aws-cdk-lib/aws-cloudfront/lib/function.ts#L291)
- Type last changed: v2.118.0 · 3 Jan 2024

## Example

```ts
const store = new cloudfront.KeyValueStore(this, 'KeyValueStore');
new cloudfront.Function(this, 'Function', {
  code: cloudfront.FunctionCode.fromInline('function handler(event) { return event.request }'),
  // Note that JS_2_0 must be used for Key Value Store support
  runtime: cloudfront.FunctionRuntime.JS_2_0,
  keyValueStore: store,
});
```

## Properties

- `JS_1_0`: [FunctionRuntime](/cdk/api/v2/docs/aws-cdk-lib.aws_cloudfront.FunctionRuntime.html) (static) — cloudfront-js-1.0.

- `JS_2_0`: [FunctionRuntime](/cdk/api/v2/docs/aws-cdk-lib.aws_cloudfront.FunctionRuntime.html) (static) — cloudfront-js-2.0.

- `value`: string

## Methods

- `custom(runtimeString: string): FunctionRuntime // chainable` (static) — A custom runtime string.

  Gives full control over the runtime string fragment.