Add support for Glimmer JS/TS

languages.json

@@ -598,6 +598,22 @@
       "quotes": [["\\\"", "\\\""]],
       "extensions": ["gleam"]
     },
+    "GlimmerJs": {
+      "name": "Glimmer JS",
+      "line_comment": ["//"],
+      "multi_line_comments": [["/*", "*/"], ["<!--", "-->"]],
+      "quotes": [["\\\"", "\\\""], ["'", "'"], ["`", "`"]],
+      "important_syntax": ["<template", "<style"],
+      "extensions": ["gjs"]
+    },
+    "GlimmerTs": {
+      "name": "Glimmer TS",
+      "line_comment": ["//"],
+      "multi_line_comments": [["/*", "*/"], ["<!--", "-->"]],
+      "quotes": [["\\\"", "\\\""], ["'", "'"], ["`", "`"]],
+      "important_syntax": ["<template", "<style"],
+      "extensions": ["gts"]
+    },
     "Glsl": {
       "name": "GLSL",
       "line_comment": ["//"],

src/language/embedding.rs

@@ -171,7 +171,9 @@ impl<'a> RegexCache<'a> {
             LanguageType::Html
             | LanguageType::RubyHtml
             | LanguageType::Svelte
-            | LanguageType::Vue => {
+            | LanguageType::Vue
+            | LanguageType::GlimmerJs
+            | LanguageType::GlimmerTs => {
                 let html = HtmlLike {
                     start_script: save_captures(&START_SCRIPT, lines, start, end),
                     start_style: save_captures(&START_STYLE, lines, start, end),

tests/data/glimmer_js.gjs

@@ -0,0 +1,27 @@
+// 27 lines, 18 code, 6 comments, 3 blanks
+import { helper } from '@ember/component/helper';
+import { modifier } from 'ember-modifier';
+
+// A single-line comment
+const plusOne = helper(([num]) => num + 1);
+
+/**
+ * A multi-line comment
+ */
+const setScrollPosition = modifier((element, [position]) => {
+  element.scrollTop = position
+});
+
+<template>
+  <!-- A HTML-like comment -->
+  <div class="scroll-container" {{setScrollPosition @scrollPos}}>
+    {{#each @items as |item index|}}
+      Item #{{plusOne index}}: {{item}}
+    {{/each}}
+  </div>
+  <style>
+    div {
+      background-color: #E04E39;
+    }
+  </style>
+</template>

tests/data/glimmer_ts.gts

@@ -0,0 +1,18 @@
+// 18 lines, 10 code, 6 comments, 2 blanks
+import type { TemplateOnlyComponent } from '@glimmer/component';
+
+// A single-line comment
+const localVariable = 'foo';
+
+/**
+ * A multi-line comment
+ */
+const Greet: TemplateOnlyComponent<{ name: string }> = <template>
+  <!-- A HTML-like comment -->
+  <p>Hello, {{@name}}! {{localVariable}}</p>
+  <style>
+    p {
+      background-color: #E04E39;
+    }
+  </style>
+</template>