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Contents
/**
* Copyright 2014-2015, 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
*/
'use strict';
var invariant = require('fbjs/lib/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(current, next) {
!(next != null) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'accumulateInto(...): Accumulated items must not be null or undefined.') : invariant(false) : 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).
var currentIsArray = Array.isArray(current);
var nextIsArray = Array.isArray(next);
if (currentIsArray && nextIsArray) {
current.push.apply(current, next);
return current;
}
if (currentIsArray) {
current.push(next);
return current;
}
if (nextIsArray) {
// A bit too dangerous to mutate `next`.
return [current].concat(next);
}
return [current, next];
}
module.exports = accumulateInto;
Version data entries
5 entries across 3 versions & 1 rubygems