GT2/Ejectable/node_modules/react-native/Libraries/Utilities/differ/deepDiffer.js

102 lines
2.8 KiB
JavaScript

/**
* Copyright (c) Facebook, Inc. and its affiliates.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
* @format
* @flow
*/
'use strict';
let logListeners;
type LogListeners = {|
+onDifferentFunctionsIgnored: (nameOne: ?string, nameTwo: ?string) => void,
|};
type Options = {|+unsafelyIgnoreFunctions?: boolean|};
function unstable_setLogListeners(listeners: ?LogListeners) {
logListeners = listeners;
}
/*
* @returns {bool} true if different, false if equal
*/
const deepDiffer = function(
one: any,
two: any,
maxDepthOrOptions: Options | number = -1,
maybeOptions?: Options,
): boolean {
const options =
typeof maxDepthOrOptions === 'number' ? maybeOptions : maxDepthOrOptions;
const maxDepth =
typeof maxDepthOrOptions === 'number' ? maxDepthOrOptions : -1;
if (maxDepth === 0) {
return true;
}
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 unless explicitly configured otherwise
let unsafelyIgnoreFunctions = options?.unsafelyIgnoreFunctions;
if (unsafelyIgnoreFunctions == null) {
if (
logListeners &&
logListeners.onDifferentFunctionsIgnored &&
(!options || !('unsafelyIgnoreFunctions' in options))
) {
logListeners.onDifferentFunctionsIgnored(one.name, two.name);
}
unsafelyIgnoreFunctions = true;
}
return !unsafelyIgnoreFunctions;
}
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;
}
if (Array.isArray(one)) {
// We know two is also an array because the constructors are equal
const len = one.length;
if (two.length !== len) {
return true;
}
for (let ii = 0; ii < len; ii++) {
if (deepDiffer(one[ii], two[ii], maxDepth - 1, options)) {
return true;
}
}
} else {
for (const key in one) {
if (deepDiffer(one[key], two[key], maxDepth - 1, options)) {
return true;
}
}
for (const 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;
module.exports.unstable_setLogListeners = unstable_setLogListeners;