You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
40 lines
1.3 KiB
40 lines
1.3 KiB
var aFunction = require('../internals/a-function');
|
|
var toObject = require('../internals/to-object');
|
|
var IndexedObject = require('../internals/indexed-object');
|
|
var toLength = require('../internals/to-length');
|
|
|
|
// `Array.prototype.{ reduce, reduceRight }` methods implementation
|
|
var createMethod = function (IS_RIGHT) {
|
|
return function (that, callbackfn, argumentsLength, memo) {
|
|
aFunction(callbackfn);
|
|
var O = toObject(that);
|
|
var self = IndexedObject(O);
|
|
var length = toLength(O.length);
|
|
var index = IS_RIGHT ? length - 1 : 0;
|
|
var i = IS_RIGHT ? -1 : 1;
|
|
if (argumentsLength < 2) while (true) {
|
|
if (index in self) {
|
|
memo = self[index];
|
|
index += i;
|
|
break;
|
|
}
|
|
index += i;
|
|
if (IS_RIGHT ? index < 0 : length <= index) {
|
|
throw TypeError('Reduce of empty array with no initial value');
|
|
}
|
|
}
|
|
for (;IS_RIGHT ? index >= 0 : length > index; index += i) if (index in self) {
|
|
memo = callbackfn(memo, self[index], index, O);
|
|
}
|
|
return memo;
|
|
};
|
|
};
|
|
|
|
module.exports = {
|
|
// `Array.prototype.reduce` method
|
|
// https://tc39.github.io/ecma262/#sec-array.prototype.reduce
|
|
left: createMethod(false),
|
|
// `Array.prototype.reduceRight` method
|
|
// https://tc39.github.io/ecma262/#sec-array.prototype.reduceright
|
|
right: createMethod(true)
|
|
};
|
|
|