Convert extend util to TypeScript

js/src/@types/global.d.ts

@@ -1,3 +1,21 @@
+/**
+ * UTILITY TYPES
+ */
+
+/**
+ * Type that returns an array of all keys of a provided object that are of
+ * of the provided type, or a subtype of the type.
+ */
+declare type KeysOfType<Type extends object, Match> = {
+  [Key in keyof Type]-?: Type[Key] extends Match ? Key : never;
+};
+
+/**
+ * Type that matches one of the keys of an object that is of the provided
+ * type, or a subtype of it.
+ */
+declare type KeyOfType<Type extends object, Match> = KeysOfType<Type, Match>[keyof Type];
+
 /**
  * @deprecated Please import `app` from a namespace instead of using it as a global variable.
  *

js/src/common/Application.tsx

@@ -14,7 +14,7 @@ import mapRoutes from './utils/mapRoutes';
 import RequestError from './utils/RequestError';
 import ScrollListener from './utils/ScrollListener';
 import liveHumanTimes from './utils/liveHumanTimes';
-import { extend } from './extend';
+import { extend } from './extend.ts';
 
 import Forum from './models/Forum';
 import User from './models/User';

js/src/common/compat.js

@@ -1,4 +1,4 @@
-import * as extend from './extend';
+import * as extend from './extend.ts';
 import Session from './Session';
 import Store from './Store';
 import BasicEditorDriver from './utils/BasicEditorDriver';

js/src/common/extend.js → js/src/common/extend.ts

@@ -19,23 +19,27 @@
  *   // something that needs to be run on creation and update
  * });
  *
- * @param {object} object The object that owns the method
- * @param {string|string[]} methods The name or names of the method(s) to extend
- * @param {function} callback A callback which mutates the method's output
+ * @param object The object that owns the method
+ * @param methods The name or names of the method(s) to extend
+ * @param callback A callback which mutates the method's output
  */
-export function extend(object, methods, callback) {
+export function extend<T extends object, K extends KeyOfType<T, Function>>(
+  object: T,
+  methods: K | K[],
+  callback: (this: T, val: ReturnType<T[K]>, ...args: Parameters<T[K]>) => void
+) {
   const allMethods = Array.isArray(methods) ? methods : [methods];
 
-  allMethods.forEach((method) => {
-    const original = object[method];
+  allMethods.forEach((method: K) => {
+    const original: Function | undefined = object[method];
 
-    object[method] = function (...args) {
+    object[method] = function (this: T, ...args: Parameters<T[K]>) {
       const value = original ? original.apply(this, args) : undefined;
 
-      callback.apply(this, [value].concat(args));
+      callback.apply(this, [value, ...args]);
 
       return value;
-    };
+    } as T[K];
 
     Object.assign(object[method], original);
   });
@@ -64,19 +68,23 @@ export function extend(object, methods, callback) {
  *   // something that needs to be run on creation and update
  * });
  *
- * @param {object} object The object that owns the method
- * @param {string|string[]} method The name or names of the method(s) to override
- * @param {function} newMethod The method to replace it with
+ * @param object The object that owns the method
+ * @param methods The name or names of the method(s) to override
+ * @param newMethod The method to replace it with
  */
-export function override(object, methods, newMethod) {
+export function override<T extends object, K extends KeyOfType<T, Function>>(
+  object: T,
+  methods: K | K[],
+  newMethod: (this: T, orig: T[K], ...args: Parameters<T[K]>) => void
+) {
   const allMethods = Array.isArray(methods) ? methods : [methods];
 
   allMethods.forEach((method) => {
-    const original = object[method];
+    const original: Function = object[method];
 
-    object[method] = function (...args) {
-      return newMethod.apply(this, [original.bind(this)].concat(args));
-    };
+    object[method] = function (this: T, ...args: Parameters<T[K]>) {
+      return newMethod.apply(this, [original.bind(this), ...args]);
+    } as T[K];
 
     Object.assign(object[method], original);
   });

js/src/common/utils/proxifyCompat.ts

@@ -1,10 +1,12 @@
-export default (compat: { [key: string]: any }, namespace: string) => {
+export default function proxifyCompat(compat: Record<string, unknown>, namespace: string) {
   // regex to replace common/ and NAMESPACE/ for core & core extensions
+  // and remove .js, .ts and .tsx extensions
   // e.g. admin/utils/extract --> utils/extract
   // e.g. tags/common/utils/sortTags --> tags/utils/sortTags
-  const regex = new RegExp(`(\\w+\\/)?(${namespace}|common)\\/`);
+  const regex = new RegExp(String.raw`(\w+\/)?(${namespace}|common)\/`);
+  const fileExt = /(\.js|\.tsx?)$/;
 
   return new Proxy(compat, {
-    get: (obj, prop: string) => obj[prop] || obj[prop.replace(regex, '$1')],
+    get: (obj, prop: string) => obj[prop] || obj[prop.replace(regex, '$1').replace(fileExt, '')],
   });
-};
+}