Vencord/src/utils/onceDefined.ts
2022-11-03 20:36:17 +01:00

48 lines
1.6 KiB
TypeScript

/*
* Vencord, a modification for Discord's desktop app
* Copyright (c) 2022 Vendicated and contributors
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
import type { LiteralUnion } from "type-fest";
/**
* Wait for a property to be defined on the target, then call the callback with
* the value
* @param target Object
* @param property Property to be defined
* @param callback Callback
*
* @example onceDefined(window, "webpackChunkdiscord_app", wpInstance => wpInstance.push(...));
*/
export function onceDefined<T, P extends LiteralUnion<keyof T, PropertyKey>>(
target: T, property: P, callback: (v: P extends keyof T ? T[P] : any) => void
): void {
const propertyAsAny = property as any;
if (property in target)
return void callback(target[propertyAsAny]);
Object.defineProperty(target, property, {
set(v) {
delete target[propertyAsAny];
target[propertyAsAny] = v;
callback(v);
},
configurable: true,
enumerable: false
});
}