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esnext.set.reduce.js
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esnext.set.reduce.js
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'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 getSetIterator = require('../internals/get-set-iterator');
var iterate = require('../internals/iterate');
// `Set.prototype.reduce` method
// https://github.com/tc39/proposal-collection-methods
$({ target: 'Set', proto: true, real: true, forced: IS_PURE }, {
reduce: function reduce(callbackfn /* , initialValue */) {
var set = anObject(this);
var iterator = getSetIterator(set);
var noInitial = arguments.length < 2;
var accumulator = noInitial ? undefined : arguments[1];
aFunction(callbackfn);
iterate(iterator, function (value) {
if (noInitial) {
noInitial = false;
accumulator = value;
} else {
accumulator = callbackfn(accumulator, value, value, set);
}
}, { IS_ITERATOR: true });
if (noInitial) throw TypeError('Reduce of empty set with no initial value');
return accumulator;
}
});