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'use strict';
var $ = require('../internals/export');
var anObject = require('../internals/an-object');
var aCallable = require('../internals/a-callable');
var getMapIterator = require('../internals/get-map-iterator');
var iterate = require('../internals/iterate');
var $TypeError = TypeError;
// `Map.prototype.reduce` method
// https://github.com/tc39/proposal-collection-methods
$({ target: 'Map', proto: true, real: true, forced: true }, {
reduce: function reduce(callbackfn /* , initialValue */) {
var map = anObject(this);
var iterator = getMapIterator(map);
var noInitial = arguments.length < 2;
var accumulator = noInitial ? undefined : arguments[1];
aCallable(callbackfn);
iterate(iterator, function (key, value) {
if (noInitial) {
noInitial = false;
accumulator = value;
} else {
accumulator = callbackfn(accumulator, value, key, map);
}
}, { AS_ENTRIES: true, IS_ITERATOR: true });
if (noInitial) throw $TypeError('Reduce of empty map with no initial value');
return accumulator;
}
});