| 'use strict'; |
| var $ = require('../internals/export'); |
| var IS_PURE = require('../internals/is-pure'); |
| var anObject = require('../internals/an-object'); |
| var aFunction = require('../internals/a-function'); |
| var getMapIterator = require('../internals/get-map-iterator'); |
| var iterate = require('../internals/iterate'); |
| |
| // `Map.prototype.reduce` method |
| // https://github.com/tc39/proposal-collection-methods |
| $({ target: 'Map', proto: true, real: true, forced: IS_PURE }, { |
| reduce: function reduce(callbackfn /* , initialValue */) { |
| var map = anObject(this); |
| var iterator = getMapIterator(map); |
| var accumulator, step; |
| aFunction(callbackfn); |
| if (arguments.length > 1) accumulator = arguments[1]; |
| else { |
| step = iterator.next(); |
| if (step.done) throw TypeError('Reduce of empty map with no initial value'); |
| accumulator = step.value[1]; |
| } |
| iterate(iterator, function (key, value) { |
| accumulator = callbackfn(accumulator, value, key, map); |
| }, undefined, true, true); |
| return accumulator; |
| } |
| }); |