library: Remove the need for noop code files

src/Document.js

@@ -68,21 +68,13 @@ async function loadSourceBuffer({ source_file, buffer, lang }) {
     buffer,
     file: source_file,
   });
-  let success;
   try {
-    success = await file_loader.load_async(GLib.PRIORITY_DEFAULT, null, null);
+    await file_loader.load_async(GLib.PRIORITY_DEFAULT, null, null);
   } catch (err) {
-    if (err.code === Gio.IOErrorEnum.NOT_FOUND) {
-      if (lang.placeholder) {
-        buffer.set_text(lang.placeholder, -1);
-      }
-      success = true;
-    } else {
+    if (err.code !== Gio.IOErrorEnum.NOT_FOUND) {
       throw err;
     }
   }
 
-  if (success) {
-    buffer.set_modified(false);
-  }
+  buffer.set_modified(false);
 }

src/Library/EntryRow.js

@@ -31,11 +31,7 @@ class EntryRow extends Adw.PreferencesRow {
   }
 
   #createLanguageTags(demo) {
-    const language = getLanguage("javascript");
-    const language_tag = this.#createLanguageTag(language);
-    this._languages_box.append(language_tag);
-
-    ["vala", "rust"].forEach((id) => {
+    ["javascript", "vala", "rust"].forEach((id) => {
       const language = getLanguage(id);
       if (!demo.languages.includes(language.id)) return;
       const language_tag = this.#createLanguageTag(language);

src/Library/Library.js

@@ -6,6 +6,7 @@ import {
   demos_dir,
   getLanguage,
   settings as global_settings,
+  languages,
 } from "../util.js";
 import Window from "../window.js";
 
@@ -71,7 +72,6 @@ export function getDemo(name) {
   return demos.find((demo) => demo.name === name);
 }
 
-const lang_javascript = getLanguage("javascript");
 async function openDemo({ application, demo_name, language }) {
   const demo = getDemo(demo_name);
   const session = createSessionFromDemo(demo);
@@ -86,9 +86,18 @@ async function openDemo({ application, demo_name, language }) {
     session.settings.set_boolean("show-code", true);
   }
 
-  const is_js =
-    session.settings.get_int("code-language") === lang_javascript.index;
+  const code_languge = session.settings.get_int("code-language");
+  const lang = languages.find((lang) => lang.index === code_languge);
 
+  // Override the user preferred language if the demo doesn't support it
+  if (demo.languages.length > 0 && !demo.languages.includes(lang.id)) {
+    session.settings.set_int(
+      "code-language",
+      getLanguage(demo.languages[0]).index,
+    );
+  }
+
+  const run = demo.autorun && lang.id === "javascript";
   const { load } = Window({ application, session });
-  await load({ run: demo.autorun && is_js });
+  await load({ run });
 }

src/util.js

@@ -83,7 +83,6 @@ export const languages = [
     extensions: [".vala"],
     types: ["text/x-vala"],
     document: null,
-    placeholder: "// Sorry, this demo is not available in Vala yet.",
     default_file: "main.vala",
     index: 1,
   },
@@ -94,7 +93,6 @@ export const languages = [
     extensions: [".rs"],
     types: ["text/x-rust"],
     document: null,
-    placeholder: "// Sorry, this demo is not available in Rust yet.",
     default_file: "code.rs",
     index: 2,
   },

src/window.js

@@ -276,74 +276,14 @@ export default function Window({ application, session }) {
     previewer.stop();
     panel_ui.stop();
 
-    const { language } = panel_code;
     try {
       await panel_ui.update();
 
       if (format) {
         await formatCode();
       }
 
-      if (language === "JavaScript") {
-        await previewer.update(true);
-
-        // We have to create a new file each time
-        // because gjs doesn't appear to use etag for module caching
-        // ?foo=Date.now() also does not work as expected
-        // TODO: File a bug
-        const [file_javascript] = Gio.File.new_tmp("workbench-XXXXXX.js");
-        await file_javascript.replace_contents_async(
-          new GLib.Bytes(document_javascript.code_view.buffer.text || " "),
-          null,
-          false,
-          Gio.FileCreateFlags.NONE,
-          null,
-        );
-        let exports;
-        try {
-          exports = await import(`file://${file_javascript.get_path()}`);
-        } catch (err) {
-          await previewer.update(true);
-          throw err;
-        } finally {
-          file_javascript
-            .delete_async(GLib.PRIORITY_DEFAULT, null)
-            .catch(console.error);
-        }
-        previewer.setSymbols(exports);
-      } else if (language === "Vala") {
-        if (!isValaEnabled()) {
-          action_extensions.activate(null);
-          return;
-        }
-
-        compiler_vala = compiler_vala || ValaCompiler({ session });
-        const success = await compiler_vala.compile();
-        if (success) {
-          await previewer.useExternal();
-          if (await compiler_vala.run()) {
-            await previewer.open();
-          } else {
-            await previewer.useInternal();
-          }
-        }
-      } else if (language === "Rust") {
-        if (!isRustEnabled()) {
-          action_extensions.activate(null);
-          return;
-        }
-
-        compiler_rust = compiler_rust || RustCompiler({ session });
-        const success = await compiler_rust.compile();
-        if (success) {
-          await previewer.useExternal();
-          if (await compiler_rust.run()) {
-            await previewer.open();
-          } else {
-            await previewer.useInternal();
-          }
-        }
-      }
+      await compile();
     } catch (err) {
       // prettier xml errors are not instances of Error
       if (err instanceof Error || err instanceof GLib.Error) {
@@ -360,6 +300,78 @@ export default function Window({ application, session }) {
     term_console.scrollToEnd();
   }
 
+  async function compile() {
+    const { language } = panel_code;
+
+    const lang = langs[language.toLowerCase()];
+    // Do nothing if there is no code to avoid compile errors
+    const text = lang.document.code_view.buffer.text.trim();
+    if (text === "") {
+      return;
+    }
+
+    if (language === "JavaScript") {
+      await previewer.update(true);
+
+      // We have to create a new file each time
+      // because gjs doesn't appear to use etag for module caching
+      // ?foo=Date.now() also does not work as expected
+      // TODO: File a bug
+      const [file_javascript] = Gio.File.new_tmp("workbench-XXXXXX.js");
+      await file_javascript.replace_contents_async(
+        new GLib.Bytes(text),
+        null,
+        false,
+        Gio.FileCreateFlags.NONE,
+        null,
+      );
+      let exports;
+      try {
+        exports = await import(`file://${file_javascript.get_path()}`);
+      } catch (err) {
+        await previewer.update(true);
+        throw err;
+      } finally {
+        file_javascript
+          .delete_async(GLib.PRIORITY_DEFAULT, null)
+          .catch(console.error);
+      }
+      previewer.setSymbols(exports);
+    } else if (language === "Vala") {
+      if (!isValaEnabled()) {
+        action_extensions.activate(null);
+        return;
+      }
+
+      compiler_vala = compiler_vala || ValaCompiler({ session });
+      const success = await compiler_vala.compile();
+      if (success) {
+        await previewer.useExternal();
+        if (await compiler_vala.run()) {
+          await previewer.open();
+        } else {
+          await previewer.useInternal();
+        }
+      }
+    } else if (language === "Rust") {
+      if (!isRustEnabled()) {
+        action_extensions.activate(null);
+        return;
+      }
+
+      compiler_rust = compiler_rust || RustCompiler({ session });
+      const success = await compiler_rust.compile();
+      if (success) {
+        await previewer.useExternal();
+        if (await compiler_rust.run()) {
+          await previewer.open();
+        } else {
+          await previewer.useInternal();
+        }
+      }
+    }
+  }
+
   const action_run = new Gio.SimpleAction({
     name: "run",
   });