feat(html): implement complete Glimmer template syntax support

.changeset/glimmer-template-support.md

@@ -0,0 +1,20 @@
+---
+"@biomejs/biome": minor
+---
+
+Added support for Glimmer template files (`.gjs` and `.gts`). Biome can now parse, format, and lint Glimmer Component files used in Ember.js applications.
+
+Glimmer templates are recognized using the `<template>...</template>` syntax and can appear in:
+- Variable assignments: `const Tpl = <template>...</template>;`
+- Class bodies: `class C { <template>...</template> }`
+- Expression contexts
+- Single unassigned templates (treated as default exports)
+
+**Phase 1 Implementation Notes:**
+- Template content is treated as **opaque tokens** - the content is preserved exactly as written without internal parsing or linting
+- The template syntax itself is validated (e.g., checking for unclosed tags)
+- Templates work with whitespace in the opening tag (e.g., `<template >`, `<template\n>`)
+- LSP language IDs "gjs" and "gts" are now recognized
+- Future phases will add internal template parsing and linting support
+
+The template content is preserved as-is during formatting, and the parser provides diagnostics for unclosed template tags.

crates/biome_grit_patterns/src/grit_js_parser.rs

@@ -2,7 +2,7 @@ use crate::{
     grit_analysis_ext::GritAnalysisExt, grit_target_language::GritTargetParser,
     grit_tree::GritTargetTree,
 };
-use biome_js_parser::{JsParserOptions, parse};
+use biome_js_parser::{JsParserOptions, parse, parse_with_options};
 use biome_js_syntax::{JsFileSource, JsLanguage};
 use biome_parser::AnyParse;
 use camino::Utf8Path;
@@ -34,7 +34,7 @@ impl GritTargetParser for GritJsParser {
             _ => JsFileSource::ts(),
         };
 
-        parse(source, source_type, JsParserOptions::default()).into()
+        parse(source, source_type).into()
     }
 }
 
@@ -48,7 +48,7 @@ impl Parser for GritJsParser {
         logs: &mut AnalysisLogs,
         _old_tree: FileOrigin<'_, GritTargetTree>,
     ) -> Option<GritTargetTree> {
-        let parse_result = parse(
+        let parse_result = parse_with_options(
             body,
             JsFileSource::tsx(),
             JsParserOptions::default().with_metavariables(),
@@ -75,7 +75,7 @@ impl Parser for GritJsParser {
             |src: &str| src.len() as u32
         };
 
-        let parse_result = parse(
+        let parse_result = parse_with_options(
             &context,
             JsFileSource::tsx(),
             JsParserOptions::default().with_metavariables(),

crates/biome_grit_patterns/src/grit_target_language/js_target_language/generated_mappings.rs

@@ -298,6 +298,7 @@ pub fn kind_by_name(node_name: &str) -> Option<JsSyntaxKind> {
         "JsFunctionExpression" => lang::JsFunctionExpression::KIND_SET.iter().next(),
         "JsGetterClassMember" => lang::JsGetterClassMember::KIND_SET.iter().next(),
         "JsGetterObjectMember" => lang::JsGetterObjectMember::KIND_SET.iter().next(),
+        "JsGlimmerTemplate" => lang::JsGlimmerTemplate::KIND_SET.iter().next(),
         "JsIdentifierAssignment" => lang::JsIdentifierAssignment::KIND_SET.iter().next(),
         "JsIdentifierBinding" => lang::JsIdentifierBinding::KIND_SET.iter().next(),
         "JsIdentifierExpression" => lang::JsIdentifierExpression::KIND_SET.iter().next(),