iter-tools-es/impls/$zip/async-zip.js

The iterable toolbox

const {
  asyncIterableCurry
} = require('../../internal/async-iterable.js');

const {
  asyncParallelEach
} = require('../../internal/async-parallel-each.js');

const {
  __asyncPeekerate
} = require('../$peekerate/async-peekerate.js');

const {
  __asyncMap
} = require('../$map/async-map.js');

const {
  __map
} = require('../$map/map.js');

const {
  __some
} = require('../$some/some.js');

const {
  __asyncToArray
} = require('../$to-array/async-to-array.js');

const isDone = peekr => peekr.done;

async function* __asyncZip(sources) {
  const peekrs = await __asyncToArray(__asyncMap(sources, __asyncPeekerate));

  let done = __some(peekrs, isDone);

  try {
    while (!done) {
      yield peekrs.map(({
        value
      }) => value);
      await Promise.all(__map(peekrs, peekr => peekr.advance()));
      done = __some(peekrs, isDone);
    }
  } finally {
    await asyncParallelEach(peekrs, peekr => peekr.return());
  }
}

exports.__asyncZip = __asyncZip;
const asyncZip = /*#__PURE__*/asyncIterableCurry(__asyncZip, {
  variadic: true
});
exports.asyncZip = asyncZip;