mattermost-mobile/app/mm-redux/utils/deep_freeze.ts
Miguel Alatzar 2d81b497cf [MM-23520] Port mattermost-redux (#4088)
* Remove mattermost-redux

* Move mm-redux files into app/redux

* Add @redux path to tsconfig.json

* Fix imports

* Install missing dependencies

* Fix tsc errors

* Fix i18n_utils test

* Fix more imports

* Remove redux websocket

* Fix tests

* Rename @redux

* Apply changes from mattermost-redux PR 1103

* Remove mattermost-redux mention in template

* Add missing imports

* Rename app/redux/ to app/mm-redux/

* Remove test file

* Fix fetching Sidebar GM profiles

Co-authored-by: Elias Nahum <nahumhbl@gmail.com>
2020-04-17 21:12:09 -07:00

67 lines
2.3 KiB
TypeScript

/**
* Copyright (c) 2015-present, 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.
*
*/
/* eslint-disable header/header */
/**
* If your application is accepting different values for the same field over
* time and is doing a diff on them, you can either (1) create a copy or
* (2) ensure that those values are not mutated behind two passes.
* This function helps you with (2) by freezing the object and throwing if
* the user subsequently modifies the value.
*
* There are two caveats with this function:
* - If the call site is not in strict mode, it will only throw when
* mutating existing fields, adding a new one
* will unfortunately fail silently :(
* - If the object is already frozen or sealed, it will not continue the
* deep traversal and will leave leaf nodes unfrozen.
*
* Freezing the object and adding the throw mechanism is expensive and will
* only be used in DEV.
*/
export default function deepFreezeAndThrowOnMutation(object: any): any {
// Some objects in IE11 don't have a hasOwnProperty method so don't even bother trying to freeze them
if (typeof object !== 'object' || object === null || Object.isFrozen(object) || Object.isSealed(object)) {
return object;
}
for (const key in object) {
if (object.hasOwnProperty(key)) {
object.__defineGetter__(key, identity.bind(null, object[key])); // eslint-disable-line no-underscore-dangle
object.__defineSetter__(key, throwOnImmutableMutation.bind(null, key)); // eslint-disable-line no-underscore-dangle
}
}
Object.freeze(object);
Object.seal(object);
for (const key in object) {
if (object.hasOwnProperty(key)) {
deepFreezeAndThrowOnMutation(object[key]);
}
}
return object;
}
function throwOnImmutableMutation(key: string, value: any) {
throw Error(
'You attempted to set the key `' + key + '` with the value `' +
JSON.stringify(value) + '` on an object that is meant to be immutable ' +
'and has been frozen.'
);
}
function identity(value: any): any {
return value;
}