callbag-to-awaitable

/**

• callbag-to-awaitable

• ---

• Use the async/await syntax with pullable Callbags! There are actually no
• Promises in this package, just async-await syntax on objects with a then
• method.
• npm install callbag-to-awaitable
• Example: on an async pullable callbag source, apply some operators, then
• convert to an awaitable and consume it in an async/await function:

• const {pipe, take, map} = require('callbag-basics');
  

• const toAwaitable = require('callbag-to-awaitable');
  

• function pullableAsyncSource(start, sink) {
  

•   if (start !== 0) return;
  

•   let i = 0;
  

•   sink(0, t => {
  

•     if (t === 1) {
  

•       setTimeout(() => { sink(1, i++) }, 1000);
  

•     }
  

•   });
  

• }
  

• const source = pipe(
  

•   pullableAsyncSource, // 0, 1, 2, 3, 4, 5, 6, 7...
  

•   take(5), // 0, 1, 2, 3, 4
  

•   map(x => x / 4) // 0, 0.25, 0.5, 0.75, 1
  

• );
  

• async function main() {
  

•   const next = toAwaitable(source);
  

•   try {
  

•     while (true) {
  

•       const x = await next;
  

•       console.log(x);
  

•     }
  

•   } catch (end) {
  

•     console.log('done');
  

•   }
  

• }
  

• main()
  

• // 0
  

• // 0.25
  

• // 0.5
  

• // 0.75
  

• // 1
  

• // done
  

• For more inquiries, read or fork the source below:
  */

function toAwaitable(source) { let talkback; let resolve; let reject; let reason = false; source(0, (t, d) => { if (t === 0) talkback = d; if (t === 1 && resolve) resolve(d); if (t === 2) { reason = d || true; if (reject) reject(reason); } resolve = void 0; reject = void 0; }); return { then: (_resolve, _reject) => { if (reason) _reject(reason); resolve = _resolve; reject = _reject; if (talkback) talkback(1); }, }; }

module.exports = toAwaitable;