deno.land / std@0.224.0 / streams / limited_transform_stream.ts
123456789101112131415161718192021222324252627282930313233343536373839// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * A {@linkcode TransformStream} that will only read & enqueue `size` amount of * chunks. * * If `options.error` is set, then instead of terminating the stream, * an error will be thrown. * * @example * ```ts * import { LimitedTransformStream } from "https://deno.land/std@$STD_VERSION/streams/limited_transform_stream.ts"; * const res = await fetch("https://example.com"); * const parts = res.body!.pipeThrough(new LimitedTransformStream(50)); * ``` */export class LimitedTransformStream<T> extends TransformStream<T, T> { #read = 0;
/** Constructs a new instance. */ constructor(size: number, options: { error?: boolean } = {}) { super({ transform: (chunk, controller) => { if ((this.#read + 1) > size) { if (options.error) { throw new RangeError(`Exceeded chunk limit of '${size}'`); } else { controller.terminate(); } } else { this.#read++; controller.enqueue(chunk); } }, }); }}
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