core-js/modules/$.collection.js

Standard library

'use strict';
var global     = require('./$.global')
  , $def       = require('./$.def')
  , forOf      = require('./$.for-of')
  , strictNew  = require('./$.strict-new');

module.exports = function(NAME, wrapper, methods, common, IS_MAP, IS_WEAK){
  var Base  = global[NAME]
    , C     = Base
    , ADDER = IS_MAP ? 'set' : 'add'
    , proto = C && C.prototype
    , O     = {};
  var fixMethod = function(KEY){
    var fn = proto[KEY];
    require('./$.redef')(proto, KEY,
      KEY == 'delete' ? function(a){ return fn.call(this, a === 0 ? 0 : a); }
      : KEY == 'has' ? function has(a){ return fn.call(this, a === 0 ? 0 : a); }
      : KEY == 'get' ? function get(a){ return fn.call(this, a === 0 ? 0 : a); }
      : KEY == 'add' ? function add(a){ fn.call(this, a === 0 ? 0 : a); return this; }
      : function set(a, b){ fn.call(this, a === 0 ? 0 : a, b); return this; }
    );
  };
  if(typeof C != 'function' || !(IS_WEAK || proto.forEach && !require('./$.fails')(function(){
    new C().entries().next();
  }))){
    // create collection constructor
    C = common.getConstructor(wrapper, NAME, IS_MAP, ADDER);
    require('./$.mix')(C.prototype, methods);
  } else {
    var inst  = new C
      , chain = inst[ADDER](IS_WEAK ? {} : -0, 1)
      , buggyZero;
    // wrap for init collections from iterable
    if(!require('./$.iter-detect')(function(iter){ new C(iter); })){ // eslint-disable-line no-new
      C = wrapper(function(target, iterable){
        strictNew(target, C, NAME);
        var that = new Base;
        if(iterable != undefined)forOf(iterable, IS_MAP, that[ADDER], that);
        return that;
      });
      C.prototype = proto;
      proto.constructor = C;
    }
    IS_WEAK || inst.forEach(function(val, key){
      buggyZero = 1 / key === -Infinity;
    });
    // fix converting -0 key to +0
    if(buggyZero){
      fixMethod('delete');
      fixMethod('has');
      IS_MAP && fixMethod('get');
    }
    // + fix .add & .set for chaining
    if(buggyZero || chain !== inst)fixMethod(ADDER);
    // weak collections should not contains .clear method
    if(IS_WEAK && proto.clear)delete proto.clear;
  }

  require('./$.tag')(C, NAME);

  O[NAME] = C;
  $def($def.G + $def.W + $def.F * (C != Base), O);

  if(!IS_WEAK)common.setStrong(C, NAME, IS_MAP);

  return C;
};