core-js/internals/async-iterator-iteration.js

'use strict';
// https://github.com/tc39/proposal-iterator-helpers
// https://github.com/tc39/proposal-array-from-async
var call = require('../internals/function-call');
var aCallable = require('../internals/a-callable');
var anObject = require('../internals/an-object');
var isObject = require('../internals/is-object');
var doesNotExceedSafeInteger = require('../internals/does-not-exceed-safe-integer');
var getBuiltIn = require('../internals/get-built-in');
var getIteratorDirect = require('../internals/get-iterator-direct');
var closeAsyncIteration = require('../internals/async-iterator-close');

var createMethod = function (TYPE) {
  var IS_TO_ARRAY = TYPE === 0;
  var IS_FOR_EACH = TYPE === 1;
  var IS_EVERY = TYPE === 2;
  var IS_SOME = TYPE === 3;
  return function (object, fn, target) {
    anObject(object);
    var MAPPING = fn !== undefined;
    if (MAPPING || !IS_TO_ARRAY) aCallable(fn);
    var record = getIteratorDirect(object);
    var Promise = getBuiltIn('Promise');
    var iterator = record.iterator;
    var next = record.next;
    var counter = 0;

    return new Promise(function (resolve, reject) {
      var ifAbruptCloseAsyncIterator = function (error) {
        closeAsyncIteration(iterator, reject, error, reject);
      };

      var loop = function () {
        try {
          if (MAPPING) try {
            doesNotExceedSafeInteger(counter);
          } catch (error5) { ifAbruptCloseAsyncIterator(error5); }
          Promise.resolve(anObject(call(next, iterator))).then(function (step) {
            try {
              if (anObject(step).done) {
                if (IS_TO_ARRAY) {
                  target.length = counter;
                  resolve(target);
                } else resolve(IS_SOME ? false : IS_EVERY || undefined);
              } else {
                var value = step.value;
                try {
                  if (MAPPING) {
                    var result = fn(value, counter);

                    var handler = function ($result) {
                      if (IS_FOR_EACH) {
                        loop();
                      } else if (IS_EVERY) {
                        $result ? loop() : closeAsyncIteration(iterator, resolve, false, reject);
                      } else if (IS_TO_ARRAY) {
                        try {
                          target[counter++] = $result;
                          loop();
                        } catch (error4) { ifAbruptCloseAsyncIterator(error4); }
                      } else {
                        $result ? closeAsyncIteration(iterator, resolve, IS_SOME || value, reject) : loop();
                      }
                    };

                    if (isObject(result)) Promise.resolve(result).then(handler, ifAbruptCloseAsyncIterator);
                    else handler(result);
                  } else {
                    target[counter++] = value;
                    loop();
                  }
                } catch (error3) { ifAbruptCloseAsyncIterator(error3); }
              }
            } catch (error2) { reject(error2); }
          }, reject);
        } catch (error) { reject(error); }
      };

      loop();
    });
  };
};

module.exports = {
  toArray: createMethod(0),
  forEach: createMethod(1),
  every: createMethod(2),
  some: createMethod(3),
  find: createMethod(4)
};