mirror of
https://github.com/facebook/react.git
synced 2025-11-01 09:12:30 +00:00
Sebastian Markbåge
c625bc88aa
This moves some files out of shared that are not actually shared
with isomorphic. They're specific to the renderers.
(cherry picked from commit 4bc1048e0d)
60 lines
1.6 KiB
JavaScript
60 lines
1.6 KiB
JavaScript
/**
|
|
* Copyright 2014-present, Facebook, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This source code is licensed under the BSD-style license found in the
|
|
* LICENSE file in the root directory of this source tree. An additional grant
|
|
* of patent rights can be found in the PATENTS file in the same directory.
|
|
*
|
|
* @providesModule accumulateInto
|
|
* @flow
|
|
*/
|
|
|
|
'use strict';
|
|
|
|
var invariant = require('invariant');
|
|
|
|
/**
|
|
* Accumulates items that must not be null or undefined into the first one. This
|
|
* is used to conserve memory by avoiding array allocations, and thus sacrifices
|
|
* API cleanness. Since `current` can be null before being passed in and not
|
|
* null after this function, make sure to assign it back to `current`:
|
|
*
|
|
* `a = accumulateInto(a, b);`
|
|
*
|
|
* This API should be sparingly used. Try `accumulate` for something cleaner.
|
|
*
|
|
* @return {*|array<*>} An accumulation of items.
|
|
*/
|
|
|
|
function accumulateInto<T>(current: ?(T | Array<T>), next: T | Array<T>): T | Array<T> {
|
|
invariant(
|
|
next != null,
|
|
'accumulateInto(...): Accumulated items must not be null or undefined.'
|
|
);
|
|
|
|
if (current == null) {
|
|
return next;
|
|
}
|
|
|
|
// Both are not empty. Warning: Never call x.concat(y) when you are not
|
|
// certain that x is an Array (x could be a string with concat method).
|
|
if (Array.isArray(current)) {
|
|
if (Array.isArray(next)) {
|
|
current.push.apply(current, next);
|
|
return current;
|
|
}
|
|
current.push(next);
|
|
return current;
|
|
}
|
|
|
|
if (Array.isArray(next)) {
|
|
// A bit too dangerous to mutate `next`.
|
|
return [current].concat(next);
|
|
}
|
|
|
|
return [current, next];
|
|
}
|
|
|
|
module.exports = accumulateInto;
|