https://github.com/sail-sail/through2

A tiny wrapper around Node.js streams.Transform (Streams2/3) to avoid explicit subclassing noise
https://github.com/sail-sail/through2

Last synced: 21 days ago
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A tiny wrapper around Node.js streams.Transform (Streams2/3) to avoid explicit subclassing noise

• Host: GitHub
• URL: https://github.com/sail-sail/through2
• Owner: sail-sail
• License: mit
• Created: 2022-05-23T03:43:33.000Z (over 2 years ago)
• Default Branch: main
• Last Pushed: 2022-05-23T08:02:28.000Z (over 2 years ago)
• Last Synced: 2024-10-04T13:11:51.297Z (about 1 month ago)
• Language: JavaScript
• Size: 4.88 KB
• Stars: 0
• Watchers: 2
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# through2

A tiny wrapper around Node.js streams.Transform (Streams2/3) to avoid explicit subclassing noise

Inspired by Dominic Tarr's through in that it's so much easier to make a stream out of a function than it is to set up the prototype chain properly: through(function (chunk) { ... }).

fock by https://github.com/rvagg/through2

## usage

```ts

import { assertEquals } from "https://deno.land/[email protected]/testing/asserts.ts";

import { make as through2 } from "https://deno.land/x/[email protected]/mod.ts";

import { Buffer } from "https://deno.land/[email protected]/node/buffer.ts";

import { BufferListStream } from "https://raw.githubusercontent.com/sail-sail/buffer_list/main/mod.ts";

function randomBytes(len) {

  const bytes = new Uint8Array(len)

  for (let i = 0; i < len; i++) {

    bytes[i] = Math.floor(Math.random() * 0xff)

  }

  return bytes

}

Deno.test("through2", function() {

  const th2 = through2(function (chunk, _enc, callback) {

    if (!this._i) {

      this._i = 97;

    } else {

      this._i++;

    }

    const b = Buffer.alloc(chunk.length)

    for (let i = 0; i < chunk.length; i++) {

      b[i] = this._i;

    }

    this.push(b);

    callback();

  });

  th2.pipe(new BufferListStream((err, b) => {

    if (err) {

      throw err;

    }

    const s = b.toString('ascii');

    assertEquals(s, "aaaaaaaaaabbbbbcccccccccc");

  }));

  th2.write(randomBytes(10));

  th2.write(randomBytes(5));

  th2.write(randomBytes(10));

  th2.end();

});

```