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

The iterable toolbox

const {
  iterableCurry
} = require('../../internal/iterable.js');

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

const {
  __peekerate
} = require('../$peekerate/peekerate.js');

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

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

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

const isDone = peekr => peekr.done;

function* __zip(sources) {
  const peekrs = __toArray(__map(sources, __peekerate));

  let done = __some(peekrs, isDone);

  try {
    while (!done) {
      yield peekrs.map(({
        value
      }) => value);

      for (const peekr of peekrs) peekr.advance();

      done = __some(peekrs, isDone);
    }
  } finally {
    parallelEach(peekrs, peekr => peekr.return());
  }
}

exports.__zip = __zip;
const zip = /*#__PURE__*/iterableCurry(__zip, {
  variadic: true
});
exports.zip = zip;