react-native/Libraries/Utilities/differ/deepDiffer.js

49 lines
1.2 KiB
JavaScript

/**
* Copyright 2004-present Facebook. All Rights Reserved.
*
* @providesModule deepDiffer
* @flow
*/
'use strict';
/*
* @returns {bool} true if different, false if equal
*/
var deepDiffer = function(one: any, two: any): bool {
if (one === two) {
// Short circuit on identical object references instead of traversing them.
return false;
}
if ((typeof one === 'function') && (typeof two === 'function')) {
// We consider all functions equal
return false;
}
if ((typeof one !== 'object') || (one === null)) {
// Primitives can be directly compared
return one !== two;
}
if ((typeof two !== 'object') || (two === null)) {
// We know they are different because the previous case would have triggered
// otherwise.
return true;
}
if (one.constructor !== two.constructor) {
return true;
}
for (var key in one) {
if (deepDiffer(one[key], two[key])) {
return true;
}
}
for (var twoKey in two) {
// The only case we haven't checked yet is keys that are in two but aren't
// in one, which means they are different.
if (one[twoKey] === undefined && two[twoKey] !== undefined) {
return true;
}
}
return false;
};
module.exports = deepDiffer;