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.
29 lines
1.0 KiB
29 lines
1.0 KiB
import isArrayLike from './_isArrayLike.js';
|
|
import keys from './keys.js';
|
|
import optimizeCb from './_optimizeCb.js';
|
|
|
|
// Internal helper to create a reducing function, iterating left or right.
|
|
export default function createReduce(dir) {
|
|
// Wrap code that reassigns argument variables in a separate function than
|
|
// the one that accesses `arguments.length` to avoid a perf hit. (#1991)
|
|
var reducer = function(obj, iteratee, memo, initial) {
|
|
var _keys = !isArrayLike(obj) && keys(obj),
|
|
length = (_keys || obj).length,
|
|
index = dir > 0 ? 0 : length - 1;
|
|
if (!initial) {
|
|
memo = obj[_keys ? _keys[index] : index];
|
|
index += dir;
|
|
}
|
|
for (; index >= 0 && index < length; index += dir) {
|
|
var currentKey = _keys ? _keys[index] : index;
|
|
memo = iteratee(memo, obj[currentKey], currentKey, obj);
|
|
}
|
|
return memo;
|
|
};
|
|
|
|
return function(obj, iteratee, memo, context) {
|
|
var initial = arguments.length >= 3;
|
|
return reducer(obj, optimizeCb(iteratee, context, 4), memo, initial);
|
|
};
|
|
}
|