| 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 | import is from './objectIs'; |
| 11 | import hasOwnProperty from './hasOwnProperty'; |
| 12 | |
| 13 | /** |
| 14 | * Performs equality by iterating through keys on an object and returning false |
| 15 | * when any key has values which are not strictly equal between the arguments. |
| 16 | * Returns true when the values of all keys are strictly equal. |
| 17 | */ |
| 18 | function shallowEqual(objA: mixed, objB: mixed): boolean { |
| 19 | if (is(objA, objB)) { |
| 20 | return true; |
| 21 | } |
| 22 | |
| 23 | if ( |
| 24 | typeof objA !== 'object' || |
| 25 | objA === null || |
| 26 | typeof objB !== 'object' || |
| 27 | objB === null |
| 28 | ) { |
| 29 | return false; |
| 30 | } |
| 31 | |
| 32 | const keysA = Object.keys(objA); |
| 33 | const keysB = Object.keys(objB); |
| 34 | |
| 35 | if (keysA.length !== keysB.length) { |
| 36 | return false; |
| 37 | } |
| 38 | |
| 39 | // Test for A's keys different from B. |
| 40 | for (let i = 0; i < keysA.length; i++) { |
| 41 | const currentKey = keysA[i]; |
| 42 | if ( |
| 43 | !hasOwnProperty.call(objB, currentKey) || |
| 44 | // $FlowFixMe[incompatible-use] lost refinement of `objB` |
| 45 | !is(objA[currentKey], objB[currentKey]) |
| 46 | ) { |
| 47 | return false; |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | return true; |
| 52 | } |
| 53 | |
| 54 | export default shallowEqual; |