[skip ci] Refactor utils

1 files changed, 87 insertions, 0 deletions

diff --git a/src/utils/lazy.ts b/src/utils/lazy.ts
new file mode 100644
index 0000000..1e1dd5f
--- /dev/null
+++ b/src/utils/lazy.ts
@@ -0,0 +1,87 @@
+/*
+ * 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/>.
+*/
+
+export function makeLazy<T>(factory: () => T): () => T {
+    let cache: T;
+    return () => cache ?? (cache = factory());
+}
+
+// Proxies demand that these properties be unmodified, so proxyLazy
+// will always return the function default for them.
+const unconfigurable = ["arguments", "caller", "prototype"];
+
+const handler: ProxyHandler<any> = {};
+
+const GET_KEY = Symbol.for("vencord.lazy.get");
+const CACHED_KEY = Symbol.for("vencord.lazy.cached");
+
+for (const method of [
+    "apply",
+    "construct",
+    "defineProperty",
+    "deleteProperty",
+    "get",
+    "getOwnPropertyDescriptor",
+    "getPrototypeOf",
+    "has",
+    "isExtensible",
+    "ownKeys",
+    "preventExtensions",
+    "set",
+    "setPrototypeOf"
+]) {
+    handler[method] =
+        (target: any, ...args: any[]) => Reflect[method](target[GET_KEY](), ...args);
+}
+
+handler.ownKeys = target => {
+    const v = target[GET_KEY]();
+    const keys = Reflect.ownKeys(v);
+    for (const key of unconfigurable) {
+        if (!keys.includes(key)) keys.push(key);
+    }
+    return keys;
+};
+
+handler.getOwnPropertyDescriptor = (target, p) => {
+    if (typeof p === "string" && unconfigurable.includes(p))
+        return Reflect.getOwnPropertyDescriptor(target, p);
+
+    const descriptor = Reflect.getOwnPropertyDescriptor(target[GET_KEY](), p);
+
+    if (descriptor) Object.defineProperty(target, p, descriptor);
+    return descriptor;
+};
+
+/**
+ * Wraps the result of {@see makeLazy} in a Proxy you can consume as if it wasn't lazy.
+ * On first property access, the lazy is evaluated
+ * @param factory lazy factory
+ * @returns Proxy
+ *
+ * Note that the example below exists already as an api, see {@link findByPropsLazy}
+ * @example const mod = proxyLazy(() => findByProps("blah")); console.log(mod.blah);
+ */
+export function proxyLazy<T>(factory: () => T): T {
+    const proxyDummy: { (): void;[CACHED_KEY]?: T;[GET_KEY](): T; } = Object.assign(function () { }, {
+        [CACHED_KEY]: void 0,
+        [GET_KEY]: () => proxyDummy[CACHED_KEY] ??= factory(),
+    });
+
+    return new Proxy(proxyDummy, handler) as any;
+}