'use strict';
/**
- callbag-concat
*
- Callbag factory that concatenates the data from multiple (2 or more)
- callbag sources. It starts each source at a time: waits for the previous
- source to end before starting the next source. Works with both pullable
- and listenable sources. *
npm install callbag-concat
*- Example: *
- const fromIter = require('callbag-from-iter');
- const iterate = require('callbag-iterate');
- const concat = require('callbag-concat'); *
- const source = concat(fromIter([10,20,30]), fromIter(['a','b'])); *
- iterate(x => console.log(x))(source); // 10
- // 20
- // 30
- // a
- // b */
const UNIQUE = {};
const concat = (...sources) => (start, sink) => { if (start !== 0) return; const n = sources.length; if (n === 0) { sink(0, () => {}); sink(2); return; } let i = 0; let sourceTalkback; let lastPull = UNIQUE; const talkback = (t, d) => { if (t === 1) lastPull = d; sourceTalkback(t, d); }; (function next() { if (i === n) { sink(2); return; } sourcesi => { if (t === 0) { sourceTalkback = d; if (i === 0) sink(0, talkback); else if (lastPull !== UNIQUE) sourceTalkback(1, lastPull); } else if (t === 2 && d) { sink(2, d); } else if (t === 2) { i++; next(); } else { sink(t, d); } }); })(); };
module.exports = concat;