TSSLint

TSSLint is a minimalist diagnostic extension interface built on the TypeScript Language Server (tsserver). It provides zero default rules, allowing developers to implement custom rules that complement TypeScript's native checks with minimal overhead.

Motivation

TSSLint was created to solve a specific pain point: editor lag during "Auto Fix on Save".

In large-scale TypeScript projects, traditional linters (like ESLint) often cause noticeable delays when performing auto-fixes on save, as they frequently need to re-initialize type-checking or run in separate processes. By running directly as a tsserver plugin and sharing the existing type-checking context, TSSLint provides near-instant diagnostics and fixes, ensuring a smooth and uninterrupted development experience.

Key Features

• Zero Assumptions: Comes with no built-in rules. It does not enforce any specific coding style or patterns, leaving full control to the developer.
• High Performance: Runs as a tsserver plugin, sharing the existing TypeChecker instance to avoid redundant parsing and type-checking.
• Low Noise: Violations are reported as "Message" diagnostics, ensuring they don't interfere with actual compiler errors or warnings.
• Direct AST Access: Rule authoring uses native TypeScript APIs directly, without unnecessary abstraction layers.

How It Works

TSSLint integrates into tsserver via the TypeScript plugin system, leveraging the semantic information already computed by your editor.

Getting Started

1. Install

npm install @tsslint/config --save-dev

2. Configure tsslint.config.ts

import { defineConfig } from '@tsslint/config';

export default defineConfig({
  rules: {
    // Define or import your rules here
  },
});

3. Editor Integration

• VSCode:
  1. Install the TSSLint extension.
  2. Since TSSLint requires Node.js 23.6.0+ to import tsslint.config.ts, and VSCode (v1.108.0) currently bundles Node.js 22.21.1, you must configure typescript.tsserver.nodePath to point to a Node.js 23.6.0+ executable:

     {
       "typescript.tsserver.nodePath": "/path/to/node-23.6.0"
     }

• Other Editors: Configure TSSLint as a plugin in your tsconfig.json:

  {
    "compilerOptions": {
      "plugins": [{ "name": "@tsslint/typescript-plugin" }]
    }
  }

Rule Example

// rules/no-debugger.ts
import { defineRule } from '@tsslint/config';

export default defineRule(({ typescript: ts, file, report }) => {
  ts.forEachChild(file, function cb(node) {
    if (node.kind === ts.SyntaxKind.DebuggerStatement) {
      report(
        'Debugger statement is not allowed.',
        node.getStart(file),
        node.getEnd()
      );
    }
    ts.forEachChild(node, cb);
  });
});

CLI Usage

The @tsslint/cli package provides a command-line tool for CI/CD and build processes.

# Lint a project
npx tsslint --project path/to/tsconfig.json

# Auto-fix violations
npx tsslint --project path/to/tsconfig.json --fix

# Lint multiple projects
npx tsslint --project 'packages/*/tsconfig.json' --vue-project 'apps/web/tsconfig.json'

Tip

TSSLint focuses on diagnostic fixes and does not include a built-in formatter. It is recommended to run a dedicated formatter like Prettier, dprint, or oxfmt after running TSSLint with --fix.

Extensions

Ignoring Rules

import { defineConfig, createIgnorePlugin } from '@tsslint/config';

export default defineConfig({
  plugins: [
    createIgnorePlugin('tsslint-ignore', true)
  ],
});

Usage: Use // tsslint-ignore comments in your code.

Ecosystem Integration

• ESLint: Convert rules via @tsslint/eslint.
• TSLint: Convert rules via @tsslint/tslint.

Technical Notes

• Node.js: Requires 23.6.0+ (v3.0+).
• TypeScript: Incompatible with typescript-go (v7) as it does not support Language Service Plugins.

License

MIT