Thymeleaf-Language-Support

Thymeleaf-Language-Support is a VS Code extension that adds Thymeleaf awareness to HTML templates without replacing the built-in HTML language mode. It keeps HTML completion, formatting, and Emmet intact and layers Thymeleaf syntax highlighting, an expression parser, Spring controller model validation, completion, hover, navigation, and fragment tooling on top.

Requirements

• VS Code 1.116.0 or later, or a VSCodium build on the same engine.
• No Java language server, JDK, or build tool is required. Java sources are indexed directly from the workspace.

Installation

From a VSIX file

1. Download thymeleaf-language-support-<version>.vsix from the repository root.
2. Install it with one of the following:

   • Extensions view, ... menu, Install from VSIX..., then pick the file.

   • Command line:

     code --install-extension thymeleaf-language-support-1.1.1.vsix
     

     Use codium instead of code for VSCodium.

3. Reload the window when prompted.

From source

Building needs Bun and Git.

git clone https://github.com/jungho-dev/thymeleaf-language-support.git
cd thymeleaf-language-support
bun install
bun run package
code --install-extension thymeleaf-language-support-1.1.1.vsix

bun run package type-checks, bundles out/extension.js, and writes the .vsix to the project root. The file name follows the version field in package.json.

Quick Start

1. Open the folder that contains your Spring project (the one with src/main/java and src/main/resources).
2. Open any template under src/main/resources/templates/. The extension activates on HTML and Java files.
3. Wait for the first index pass. Progress and counts appear in the Thymeleaf-Language-Support output channel (Thymeleaf-Language-Support: Open Log Output).

The defaults match the standard Spring Boot layout, including multi-module workspaces. For a different layout, adjust templateGlobs, javaGlobs, messageGlobs, and staticGlobs in the settings below, then run Thymeleaf-Language-Support: Rebuild Template, Controller, and Message Index.

To silence a rule without turning diagnostics off, add its code to disabledDiagnosticCodes:

{
  "Thymeleaf-Language-Support.disabledDiagnosticCodes": ["thymeleaf-unknown-link"]
}

Features

• Highlight th:*, data-th-*, sec:*, and layout:* attributes, and tokenize ${...}, *{...}, #{...}, @{...}, ~{...}, |...|, __...__, [[...]], [(...)], /*[[...]]*/ in th:inline="javascript" blocks, parser-level comments <!--/* */-->, and prototype-only comments <!--/*/ /*/--> through an injection grammar.
• Parse every attribute value with a Thymeleaf standard expression and SpEL subset grammar and report positioned syntax errors: missing operators, unquoted text, dangling ., unmatched ternary, broken link parameters, and missing fragment selectors, on top of bracket, string, and literal-substitution structure checks.
• Index Spring controllers: model.addAttribute, ModelAndView, @ModelAttribute methods and parameters, handler command objects, @ControllerAdvice, @SessionAttributes, flash and request attributes, and the view names each handler returns. Infer the Java type of each attribute from literals, constructors, locals, parameters, fields, and service method return types.
• Index Java classes (fields, getters, Lombok @Data/@Getter/@Value, records, enums, inheritance) and validate ${user.nmae} style property chains, th:each element types, status variables, th:with locals, th:object selections, and fragment parameters. Report model attributes that no mapped controller adds.
• Validate #{...} keys and argument counts against messages*.properties, @{...} paths against controller mappings and static resources, path variables against link parameters, and fragment names and arities against the referenced template.
• Complete attribute names, model attributes, Java properties and methods, utility objects, message keys, controller URLs, static resources, template names, and fragment names.
• Hover: attribute documentation, resolved Java type and declaring controller for model attributes, property declaration site, message values per locale, matching handler for a URL, and fragment signatures.
• Navigate: go to definition and find references for model attributes, Java properties, message keys, URLs, static resources, and fragments. Document links open templates and static files directly.
• Java side: CodeLens to open the returned template and to list template usages of each model attribute, a diagnostic for view names without a template, go to definition from a view name to the template, references from an attribute literal to its template usages, and view-name completion inside return "...".
• Signature help for fragment arguments and message placeholders.
• Snippets (th-html, th:text, th:each, th-each-block, th-switch, th:fragment, th:replace, th-form, th-block, th-inline-js, th-comment, layout:decorate, sec:authorize, and more).

Commands

Settings

Diagnostics

Model validation only runs for templates that at least one indexed controller returns (directly or through a fragment include chain). Handlers that call addAllAttributes, mergeAttributes, or use non-literal attribute names mark the template as dynamic and suppress unknown-attribute reports while property checks stay active.

Development

The e2e runner picks the editor from VSCODE_EXE, then from a codium/code launcher on PATH, and otherwise downloads a stable VS Code build through @vscode/test-electron.

License

Apache-2.0. See license.md.

The extension icon is the Thymeleaf logo from thymeleaf.org. Thymeleaf is a project of The Thymeleaf Team. This extension is an independent community project and is not affiliated with or endorsed by it.