2 // https://github.com/tc39/proposal-iterator-helpers
3 var $ = require('../internals/export');
4 var iterate = require('../internals/iterate');
5 var aFunction = require('../internals/a-function');
6 var anObject = require('../internals/an-object');
8 $({ target: 'Iterator', proto: true, real: true }, {
9 reduce: function reduce(reducer /* , initialValue */) {
12 var noInitial = arguments.length < 2;
13 var accumulator = noInitial ? undefined : arguments[1];
14 iterate(this, function (value) {
19 accumulator = reducer(accumulator, value);
21 }, undefined, false, true);
22 if (noInitial) throw TypeError('Reduce of empty iterator with no initial value');