| 1 | /** |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 3 | * |
| 4 | * This source code is licensed under the MIT license found in the |
| 5 | * LICENSE file in the root directory of this source tree. |
| 6 | * |
| 7 | * @flow |
| 8 | */ |
| 9 | |
| 10 | /** |
| 11 | * @param {array} arr an "accumulation" of items which is either an Array or |
| 12 | * a single item. Useful when paired with the `accumulate` module. This is a |
| 13 | * simple utility that allows us to reason about a collection of items, but |
| 14 | * handling the case when there is exactly one item (and we do not need to |
| 15 | * allocate an array). |
| 16 | * @param {function} cb Callback invoked with each element or a collection. |
| 17 | * @param {?} [scope] Scope used as `this` in a callback. |
| 18 | */ |
| 19 | function forEachAccumulated<T>( |
| 20 | arr: ?(Array<T> | T), |
| 21 | cb: (elem: T) => void, |
| 22 | scope: ?any, |
| 23 | ) { |
| 24 | if (Array.isArray(arr)) { |
| 25 | // $FlowFixMe[incompatible-type] if `T` is an array, `cb` cannot be called |
| 26 | arr.forEach(cb, scope); |
| 27 | } else if (arr) { |
| 28 | cb.call(scope, arr); |
| 29 | } |
| 30 | } |
| 31 | |
| 32 | export default forEachAccumulated; |