ReadableBase.prototype.forEach - node__stream.d.ts - Node

method ReadableBase.prototype.forEach

Usage in Deno

```typescript import { ReadableBase } from "node:node__stream.d.ts"; ```



ReadableBase.prototype.forEach(fn: (data: any,
options?: Pick<ArrayOptions, "signal">,
) => void | Promise<void>,
options?: ArrayOptions,
): Promise<void>

This method allows iterating a stream. For each chunk in the stream the *fn* function will be called. If the *fn* function returns a promise - that promise will be `await`ed. This method is different from `for await...of` loops in that it can optionally process chunks concurrently. In addition, a `forEach` iteration can only be stopped by having passed a `signal` option and aborting the related AbortController while `for await...of` can be stopped with `break` or `return`. In either case the stream will be destroyed. This method is different from listening to the `'data'` event in that it uses the `readable` event in the underlying machinary and can limit the number of concurrent *fn* calls.

Parameters



fn: (data: any,
options?: Pick<ArrayOptions, "signal">,
) => void | Promise<void>

a function to call on each chunk of the stream. Async or not.

optional



options: ArrayOptions

Return Type

Promise<void>

a promise for when the stream has finished.