https://github.com/staltz/callbag-to-pull-stream

👜 Convert a pullable callbag source to a pull-stream source
https://github.com/staltz/callbag-to-pull-stream

Last synced: about 2 months ago
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👜 Convert a pullable callbag source to a pull-stream source

• Host: GitHub
• URL: https://github.com/staltz/callbag-to-pull-stream
• Owner: staltz
• License: mit
• Created: 2018-02-16T17:56:29.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-02-16T17:56:37.000Z (over 6 years ago)
• Last Synced: 2024-07-20T15:08:19.968Z (2 months ago)
• Language: JavaScript
• Size: 4.88 KB
• Stars: 2
• Watchers: 3
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: readme.js
  • License: LICENSE

Awesome Lists containing this project

• awesome-callbags - to-pull-stream

README

        
/**

 * callbag-to-pull-stream

 * ----------------------

 *

 * Convert a pullable callbag source to a pull-stream source.

 *

 * `npm install callbag-to-pull-stream`

 *

 * Example:

 *

 *     const pull = require('pull-stream');

 *     const {fromIter, pipe, filter, map} = require('callbag-basics');

 *     const toPullStream = require('callbag-to-pull-stream');

 *

 *     const source = pipe(

 *       fromIter([1,3,5,7,9]),

 *       filter(x => x !== 5), // 1,3,7,9

 *       map(x => x * 10) // 10,30,70,90

 *     )

 *

 *     pull(

 *       toPullStream(source),

 *       pull.filter(x => x !== 30), // 10,70,90

 *       pull.drain(x => console.log(x))

 *     )

 */

function toPullStream(source) {

  let talkback;

  let cb;

  source(0, (t, d) => {

    let _cb = cb;

    cb = void 0;

    if (t === 0) talkback = d;

    if (t === 1 && _cb) _cb(null, d);

    if (t === 2 && _cb) _cb(d || true), talkback = void 0;

  });

  return function (end, _cb) {

    cb = _cb;

    if (end) {

      if (talkback) talkback(2, end === true ? void 0 : end);

      if (cb) cb(end);

      return;

    }

    if (talkback) talkback(1);

    else cb(true);

  };

}

module.exports = toPullStream;