extension: Initial TypeScript migration

web/packages/extension/package.json

@@ -13,10 +13,15 @@
         "ruffle-core": "^0.1.0"
     },
     "devDependencies": {
+        "@tsconfig/recommended": "^1.0.1",
+        "@types/chrome": "^0.0.135",
+        "@types/firefox-webext-browser": "^82.0.0",
         "archiver": "^5.2.0",
         "json5": "^2.2.0",
         "sign-addon": "^3.3.0",
         "temp-dir": "^2.0.0",
+        "ts-loader": "^9.0.2",
+        "typescript": "^4.2.4",
         "webpack-cli": "^4.0.0"
     }
 }

web/packages/extension/tsconfig.json

@@ -0,0 +1,12 @@
+{
+    "extends": "@tsconfig/recommended/tsconfig.json",
+
+    "compilerOptions": {
+        "target": "es6",
+        "module": "esnext",
+        "moduleResolution": "node",
+    },
+
+    "include": ["src/**/*"],
+    "exclude": ["node_modules", "dist"]
+}

web/packages/extension/webpack.config.js

@@ -48,12 +48,12 @@ module.exports = (env, argv) => {
     return {
         mode,
         entry: {
-            popup: "./src/popup.js",
-            options: "./src/options.js",
-            content: "./src/content.js",
-            ruffle: "./src/ruffle.js",
-            background: "./src/background.js",
-            player: "./src/player.js",
+            popup: "./src/popup.ts",
+            options: "./src/options.ts",
+            content: "./src/content.ts",
+            ruffle: "./src/ruffle.ts",
+            background: "./src/background.ts",
+            player: "./src/player.ts",
         },
         output: {
             path: path.resolve(__dirname, "assets/dist/"),
@@ -62,12 +62,19 @@ module.exports = (env, argv) => {
         },
         module: {
             rules: [
+                {
+                    test: /\.ts$/i,
+                    use: "ts-loader",
+                },
                 {
                     test: /\.wasm$/i,
                     type: "asset/resource",
                 },
             ],
         },
+        resolve: {
+            extensions: [".ts", "..."],
+        },
         plugins: [
             new CopyPlugin({
                 patterns: [