core-js/modules/esnext.async-iterator.take.js

'use strict';
var $ = require('../internals/export');
var call = require('../internals/function-call');
var anObject = require('../internals/an-object');
var getIteratorDirect = require('../internals/get-iterator-direct');
var notANaN = require('../internals/not-a-nan');
var toPositiveInteger = require('../internals/to-positive-integer');
var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
var createIterResultObject = require('../internals/create-iter-result-object');
var IS_PURE = require('../internals/is-pure');

var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
  var state = this;
  var iterator = state.iterator;
  var returnMethod;

  if (!state.remaining--) {
    var resultDone = createIterResultObject(undefined, true);
    state.done = true;
    returnMethod = iterator['return'];
    if (returnMethod !== undefined) {
      return Promise.resolve(call(returnMethod, iterator, undefined)).then(function () {
        return resultDone;
      });
    }
    return resultDone;
  } return Promise.resolve(call(state.next, iterator)).then(function (step) {
    if (anObject(step).done) {
      state.done = true;
      return createIterResultObject(undefined, true);
    } return createIterResultObject(step.value, false);
  }).then(null, function (error) {
    state.done = true;
    throw error;
  });
});

// `AsyncIterator.prototype.take` method
// https://github.com/tc39/proposal-async-iterator-helpers
$({ target: 'AsyncIterator', proto: true, real: true, forced: IS_PURE }, {
  take: function take(limit) {
    anObject(this);
    var remaining = toPositiveInteger(notANaN(+limit));
    return new AsyncIteratorProxy(getIteratorDirect(this), {
      remaining: remaining
    });
  }
});