core-js/internals/collection.js

'use strict';
var $ = require('../internals/export');
var global = require('../internals/global');
var isForced = require('../internals/is-forced');
var redefine = require('../internals/redefine');
var InternalMetadataModule = require('../internals/internal-metadata');
var iterate = require('../internals/iterate');
var anInstance = require('../internals/an-instance');
var isObject = require('../internals/is-object');
var fails = require('../internals/fails');
var checkCorrectnessOfIteration = require('../internals/check-correctness-of-iteration');
var setToStringTag = require('../internals/set-to-string-tag');
var inheritIfRequired = require('../internals/inherit-if-required');

module.exports = function (CONSTRUCTOR_NAME, wrapper, common, IS_MAP, IS_WEAK) {
  var NativeConstructor = global[CONSTRUCTOR_NAME];
  var NativePrototype = NativeConstructor && NativeConstructor.prototype;
  var Constructor = NativeConstructor;
  var ADDER = IS_MAP ? 'set' : 'add';
  var exported = {};

  var fixMethod = function (KEY) {
    var nativeMethod = NativePrototype[KEY];
    redefine(NativePrototype, KEY,
      KEY == 'add' ? function add(value) {
        nativeMethod.call(this, value === 0 ? 0 : value);
        return this;
      } : KEY == 'delete' ? function (key) {
        return IS_WEAK && !isObject(key) ? false : nativeMethod.call(this, key === 0 ? 0 : key);
      } : KEY == 'get' ? function get(key) {
        return IS_WEAK && !isObject(key) ? undefined : nativeMethod.call(this, key === 0 ? 0 : key);
      } : KEY == 'has' ? function has(key) {
        return IS_WEAK && !isObject(key) ? false : nativeMethod.call(this, key === 0 ? 0 : key);
      } : function set(key, value) {
        nativeMethod.call(this, key === 0 ? 0 : key, value);
        return this;
      }
    );
  };

  // eslint-disable-next-line max-len
  if (isForced(CONSTRUCTOR_NAME, typeof NativeConstructor != 'function' || !(IS_WEAK || NativePrototype.forEach && !fails(function () {
    new NativeConstructor().entries().next();
  })))) {
    // create collection constructor
    Constructor = common.getConstructor(wrapper, CONSTRUCTOR_NAME, IS_MAP, ADDER);
    InternalMetadataModule.REQUIRED = true;
  } else if (isForced(CONSTRUCTOR_NAME, true)) {
    var instance = new Constructor();
    // early implementations not supports chaining
    var HASNT_CHAINING = instance[ADDER](IS_WEAK ? {} : -0, 1) != instance;
    // V8 ~ Chromium 40- weak-collections throws on primitives, but should return false
    var THROWS_ON_PRIMITIVES = fails(function () { instance.has(1); });
    // most early implementations doesn't supports iterables, most modern - not close it correctly
    // eslint-disable-next-line no-new
    var ACCEPT_ITERABLES = checkCorrectnessOfIteration(function (iterable) { new NativeConstructor(iterable); });
    // for early implementations -0 and +0 not the same
    var BUGGY_ZERO = !IS_WEAK && fails(function () {
      // V8 ~ Chromium 42- fails only with 5+ elements
      var $instance = new NativeConstructor();
      var index = 5;
      while (index--) $instance[ADDER](index, index);
      return !$instance.has(-0);
    });

    if (!ACCEPT_ITERABLES) {
      Constructor = wrapper(function (dummy, iterable) {
        anInstance(dummy, Constructor, CONSTRUCTOR_NAME);
        var that = inheritIfRequired(new NativeConstructor(), dummy, Constructor);
        if (iterable != undefined) iterate(iterable, that[ADDER], that, IS_MAP);
        return that;
      });
      Constructor.prototype = NativePrototype;
      NativePrototype.constructor = Constructor;
    }

    if (THROWS_ON_PRIMITIVES || BUGGY_ZERO) {
      fixMethod('delete');
      fixMethod('has');
      IS_MAP && fixMethod('get');
    }

    if (BUGGY_ZERO || HASNT_CHAINING) fixMethod(ADDER);

    // weak collections should not contains .clear method
    if (IS_WEAK && NativePrototype.clear) delete NativePrototype.clear;
  }

  exported[CONSTRUCTOR_NAME] = Constructor;
  $({ global: true, forced: Constructor != NativeConstructor }, exported);

  setToStringTag(Constructor, CONSTRUCTOR_NAME);

  if (!IS_WEAK) common.setStrong(Constructor, CONSTRUCTOR_NAME, IS_MAP);

  return Constructor;
};