feat: compile typescript demos to javascript at build time

build-aux/library.js

@@ -24,6 +24,8 @@ Gio._promisify(
 
 Gio._promisify(Gio.File.prototype, "copy_async", "copy_finish");
 
+Gio._promisify(Gio.Subprocess.prototype, "wait_async", "wait_finish");
+
 const loop = new GLib.MainLoop(null, false);
 
 const [pkgdatadir] = programArgs;
@@ -95,6 +97,9 @@ const demos = [];
     demos.push(demo);
   }
 
+  // compile TypeScript demos to JavaScript
+  await compileTypeScriptFiles();
+
   await Gio.File.new_for_path(pkgdatadir)
     .get_child("demos/index.json")
     .replace_contents_async(
@@ -114,6 +119,22 @@ const demos = [];
     loop.quit();
   });
 
+async function compileTypeScriptFiles() {
+  const tsc_launcher = new Gio.SubprocessLauncher();
+  tsc_launcher.set_cwd(
+    Gio.File.new_for_path(pkgdatadir).get_child("demos").get_path()
+  );
+
+  const tsc = tsc_launcher.spawnv(["tsc"]);
+  await tsc.wait_async(null);
+
+  // TODO: maybe throw when the result is false
+  const successful = tsc.get_successful();
+  tsc_launcher.close();
+
+  if (!successful) throw new Error("One or several errors happened while compiling TypeScript demos to JavaScript")
+}
+
 async function copyDemo(source, destination) {
   try {
     destination.make_directory_with_parents(null);

src/langs/typescript/meson.build

@@ -5,6 +5,13 @@ configure_file(
   configuration: bin_conf,
 )
 
+configure_file(
+  input: 'template/tsconfig.demos.json',
+  output: 'tsconfig.json',
+  install_dir: join_paths(pkgdatadir, 'demos'),
+  configuration: bin_conf,
+)
+
 configure_file(
   input: 'types/workbench.d.ts',
   output: 'workbench.d.ts',

src/langs/typescript/template/tsconfig.demos.json

@@ -0,0 +1,14 @@
+{
+  "compilerOptions": {
+    "module": "ES2022",
+    "moduleResolution": "Bundler",
+    "target": "ES2022",
+    "skipLibCheck": true,
+    "lib": ["ES2022"],
+  },
+  "include": [
+    "./**/*.ts",
+    "@pkgdatadir@/langs/typescript/gi-types/index.d.ts",
+    "@pkgdatadir@/langs/typescript/types/workbench.d.ts",
+  ]
+}