esnext.set.reduce.js•925 B
'use strict';
var $ = require('../internals/export');
var aCallable = require('../internals/a-callable');
var aSet = require('../internals/a-set');
var iterate = require('../internals/set-iterate');
var $TypeError = TypeError;
// `Set.prototype.reduce` method
// https://github.com/tc39/proposal-collection-methods
$({ target: 'Set', proto: true, real: true, forced: true }, {
reduce: function reduce(callbackfn /* , initialValue */) {
var set = aSet(this);
var noInitial = arguments.length < 2;
var accumulator = noInitial ? undefined : arguments[1];
aCallable(callbackfn);
iterate(set, function (value) {
if (noInitial) {
noInitial = false;
accumulator = value;
} else {
accumulator = callbackfn(accumulator, value, value, set);
}
});
if (noInitial) throw new $TypeError('Reduce of empty set with no initial value');
return accumulator;
}
});