node_modules/jszip/node_modules/core-js/modules/_collection.js

'use strict';
var global            = require('./_global')
  , $export           = require('./_export')
  , redefine          = require('./_redefine')
  , redefineAll       = require('./_redefine-all')
  , meta              = require('./_meta')
  , forOf             = require('./_for-of')
  , anInstance        = require('./_an-instance')
  , isObject          = require('./_is-object')
  , fails             = require('./_fails')
  , $iterDetect       = require('./_iter-detect')
  , setToStringTag    = require('./_set-to-string-tag')
  , inheritIfRequired = require('./_inherit-if-required');

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];
    redefine(proto, KEY,
      KEY == 'delete' ? function(a){
        return IS_WEAK && !isObject(a) ? false : fn.call(this, a === 0 ? 0 : a);
      } : KEY == 'has' ? function has(a){
        return IS_WEAK && !isObject(a) ? false : fn.call(this, a === 0 ? 0 : a);
      } : KEY == 'get' ? function get(a){
        return IS_WEAK && !isObject(a) ? undefined : 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 && !fails(function(){
    new C().entries().next();
  }))){
    // create collection constructor
    C = common.getConstructor(wrapper, NAME, IS_MAP, ADDER);
    redefineAll(C.prototype, methods);
    meta.NEED = true;
  } else {
    var instance             = new C
      // early implementations not supports chaining
      , HASNT_CHAINING       = instance[ADDER](IS_WEAK ? {} : -0, 1) != instance
      // V8 ~  Chromium 40- weak-collections throws on primitives, but should return false
      , THROWS_ON_PRIMITIVES = fails(function(){ instance.has(1); })
      // most early implementations doesn't supports iterables, most modern - not close it correctly
      , ACCEPT_ITERABLES     = $iterDetect(function(iter){ new C(iter); }) // eslint-disable-line no-new
      // for early implementations -0 and +0 not the same
      , BUGGY_ZERO = !IS_WEAK && fails(function(){
        // V8 ~ Chromium 42- fails only with 5+ elements
        var $instance = new C()
          , index     = 5;
        while(index--)$instance[ADDER](index, index);
        return !$instance.has(-0);
      });
    if(!ACCEPT_ITERABLES){ 
      C = wrapper(function(target, iterable){
        anInstance(target, C, NAME);
        var that = inheritIfRequired(new Base, target, C);
        if(iterable != undefined)forOf(iterable, IS_MAP, that[ADDER], that);
        return that;
      });
      C.prototype = proto;
      proto.constructor = C;
    }
    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 && proto.clear)delete proto.clear;
  }

  setToStringTag(C, NAME);

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

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

  return C;
};