> ## Documentation Index > Fetch the complete documentation index at: https://mintlify.com/rtk-ai/rtk/llms.txt > Use this file to discover all available pages before exploring further. # JavaScript/TypeScript Stack > Token-optimized tools for modern JavaScript and TypeScript development ## Overview RTK provides comprehensive support for the modern JavaScript/TypeScript ecosystem. Achieve **70-94% token savings** through: * **JSON parsing**: Structured output from linters and compilers * **Error grouping**: Group by file, rule, or error code * **Failures only**: Show only failing tests and checks * **Package manager detection**: Auto-detects pnpm/npm/yarn/npx ## Supported Tools > **ESLint** > > Linting with rule grouping (84% savings) > **TypeScript** > > Compiler errors grouped by file (83% savings) > **Next.js** > > Build/dev with route metrics (87% savings) > **Prettier** > > Format checking (70% savings) > **Vitest** > > Test failures only (99.5% savings) > **Playwright** > > E2E test results (94% savings) > **Prisma** > > Schema operations (88% savings) ## rtk lint ESLint and other linters with rule-based grouping. ### Usage ```bash theme={null} rtk lint [linter] [options] ``` ### Supported Linters * `eslint` (default) * `biome` * `oxc` (experimental) ### Examples ```bash Standard eslint theme={null} $ eslint . /path/to/project/src/components/Button.tsx 12:15 error 'React' must be in scope when using JSX react/react-in-jsx-scope 18:23 error Missing semicolon semi 24:5 warning Unexpected console statement no-console /path/to/project/src/utils/helpers.ts 8:10 error 'foo' is assigned a value but never used @typescript-eslint/no-unused-vars 15:3 error Missing semicolon semi ✖ 5 problems (4 errors, 1 warning) # 12+ lines, ~500 tokens ``` ```bash RTK lint theme={null} $ rtk lint ✗ 4 errors, 1 warning (2 files) By rule: semi: 2 errors src/components/Button.tsx:18 src/utils/helpers.ts:15 react/react-in-jsx-scope: 1 error src/components/Button.tsx:12 @typescript-eslint/no-unused-vars: 1 error src/utils/helpers.ts:8 no-console: 1 warning src/components/Button.tsx:24 # 15 lines, ~80 tokens (84% savings) ``` ### Features * **Rule grouping**: Group violations by rule ID * **Severity levels**: Separate errors and warnings * **File locations**: Show file:line for each violation * **Exit code preservation**: Safe for CI/CD ### Implementation From `src/lint_cmd.rs`: ```rust theme={null} // Forces JSON output cmd.arg("-f").arg("json"); // Parses EslintResult JSON array let results: Vec = serde_json::from_str(&stdout)?; // Groups by rule_id let mut by_rule: HashMap> = HashMap::new(); for result in results { for msg in result.messages { by_rule.entry(msg.rule_id) .or_default() .push((result.file_path, msg.line)); } } ``` ## rtk tsc TypeScript compiler errors grouped by file. ### Usage ```bash theme={null} rtk tsc [options] ``` ### Examples ```bash Standard tsc theme={null} $ tsc src/components/Button.tsx(12,15): error TS2322: Type 'string' is not assignable to type 'number'. src/components/Button.tsx(18,23): error TS2304: Cannot find name 'React'. src/utils/helpers.ts(8,10): error TS6133: 'foo' is declared but its value is never read. src/utils/helpers.ts(15,3): error TS1005: ';' expected. src/api/client.ts(42,5): error TS2345: Argument of type 'string' is not assignable to parameter of type 'number'. # 5+ lines, ~300 tokens ``` ```bash RTK tsc theme={null} $ rtk tsc ✗ 5 errors (3 files) src/components/Button.tsx (2 errors) TS2322:12 Type 'string' is not assignable to type 'number' TS2304:18 Cannot find name 'React' src/utils/helpers.ts (2 errors) TS6133:8 'foo' is declared but its value is never read TS1005:15 ';' expected src/api/client.ts (1 error) TS2345:42 Argument of type 'string' is not assignable to parameter of type 'number' # 12 lines, ~50 tokens (83% savings) ``` ### Features * **File grouping**: Group errors by file * **Error codes**: Show TypeScript error codes (TS2322, etc.) * **Line numbers**: Compact format `TScode:line` * **Context preservation**: Keep error messages ### Implementation From `src/tsc_cmd.rs`: ```rust theme={null} // Regex pattern for tsc output static ref TSC_ERROR: Regex = Regex::new( r"^(.+?)\((\d+),(\d+)\):\s+(error|warning)\s+(TS\d+):\s+(.+)$" ).unwrap(); // Groups by file let mut errors: Vec = Vec::new(); for line in output.lines() { if let Some(caps) = TSC_ERROR.captures(line) { errors.push(TsError { file: caps[1].to_string(), line: caps[2].parse()?, code: caps[5].to_string(), message: caps[6].to_string(), }); } } ``` ## rtk next Next.js build and dev with route metrics. ### Usage ```bash theme={null} rtk next [options] ``` ### Commands * `build`: Production build * `dev`: Development server * `start`: Start production server ### Examples ```bash Standard next build theme={null} $ next build ✔ Creating an optimized production build ✔ Compiled successfully ✔ Linting and checking validity of types ✔ Collecting page data ✔ Generating static pages (12/12) ✔ Collecting build traces ✔ Finalizing page optimization Route (app) Size First Load JS ┌ Λ / 142 B 87.3 kB ├ Λ /about 156 B 87.4 kB ├ Λ /blog/[slug] 234 B 87.5 kB └ Λ /api/users 0 B 87.2 kB + First Load JS shared by all 87.1 kB ├ chunks/framework-abc123.js 45.2 kB ├ chunks/main-def456.js 31.8 kB └ other shared chunks (total) 10.1 kB # 20+ lines, ~800 tokens ``` ```bash RTK next build theme={null} $ rtk next build ✓ Build successful (4 routes, 87.5 kB) / 87.3 kB /about 87.4 kB /blog/[slug] 87.5 kB /api/users 87.2 kB # 6 lines, ~100 tokens (87% savings) ``` ### Features * **Route summary**: Show all routes with sizes * **Build metrics**: Total bundle size * **Error highlighting**: Preserve build errors * **Dev mode**: Compact startup messages ## rtk prettier Format checking with files-only output. ### Usage ```bash theme={null} rtk prettier [options] ``` ### Examples ```bash Standard prettier --check theme={null} $ prettier --check . Checking formatting... src/components/Button.tsx src/utils/helpers.ts src/api/client.ts All matched files use Prettier code style! # 5+ lines, ~200 tokens ``` ```bash RTK prettier theme={null} $ rtk prettier --check . ✓ Prettier: All files formatted correctly # 1 line, ~60 tokens (70% savings) ``` ```bash Files needing formatting theme={null} $ rtk prettier --check . ⚠️ 3 files need formatting: src/components/Button.tsx src/utils/helpers.ts src/api/client.ts # 4 lines, ~50 tokens ``` ### Features * **Pass/fail summary**: Single line if all formatted * **File list**: Show only files needing changes * **Write mode**: Compact confirmation on format ## rtk vitest Vitest test runner showing failures only. ### Usage ```bash theme={null} rtk vitest [command] [options] ``` ### Examples See [Testing Commands](/commands/testing#rtk-vitest) for detailed examples. ### Token Savings **99.5% savings** on passing tests, **90% savings** on failures. ## rtk playwright Playwright E2E tests with failure grouping. ### Usage ```bash theme={null} rtk playwright test [options] ``` ### Examples ```bash Standard playwright theme={null} $ playwright test Running 24 tests using 4 workers 24 passed (1.2s) To open last HTML report run: npx playwright show-report # 10+ lines, ~150 tokens (all passing) ``` ```bash RTK playwright (all passing) theme={null} $ rtk playwright test ✓ 24 passed (1.2s) # 1 line, ~10 tokens (93% savings) ``` ```bash RTK playwright (failures) theme={null} $ rtk playwright test ✗ 2 failed, 22 passed (1.5s) tests/login.spec.ts ✗ should login with valid credentials Error: Timed out waiting for element tests/checkout.spec.ts ✗ should complete purchase Error: Expected "Success" but got "Error" # 9 lines, ~90 tokens (94% savings on 50+ line output) ``` ### Features * **Failures only**: Skip passing tests * **Suite grouping**: Group by test file * **Error messages**: Preserve failure details * **Tee recovery**: Full output saved to file ## rtk prisma Prisma CLI without ASCII art. ### Usage ```bash theme={null} rtk prisma [options] ``` ### Supported Commands * `generate`: Generate Prisma Client * `migrate dev`: Create and apply migration * `db push`: Push schema changes * `studio`: Open Prisma Studio (passthrough) ### Examples ```bash Standard prisma generate theme={null} $ prisma generate ██████╗ ██████╗ ██╗██████╗ ███╗ ██╗ ██████╗ ██╔══██╗██╔══██╗██║██╔════╝████╗ ██║██╔══██╗ Prisma schema loaded from prisma/schema.prisma Datasource "db": PostgreSQL database "mydb" Generating Prisma Client... ✔ Generated Prisma Client (4.8.1) to ./node_modules/@prisma/client in 823ms # 15+ lines, ~500 tokens ``` ```bash RTK prisma generate theme={null} $ rtk prisma generate ✓ Prisma Client generated (4.8.1) in 823ms Schema: prisma/schema.prisma Datasource: PostgreSQL (mydb) # 3 lines, ~60 tokens (88% savings) ``` ### Features * **No ASCII art**: Strips Prisma logo * **Essential info**: Schema path, datasource, timing * **Migration summaries**: Compact migration output * **Error preservation**: Full error messages on failure ## Package Manager Detection All JavaScript tools auto-detect package manager: ```rust theme={null} // From src/utils.rs pub fn package_manager_exec(tool: &str) -> Command { if has_pnpm_lock() { Command::new("pnpm").arg("exec").arg(tool) } else if has_yarn_lock() { Command::new("yarn").arg("exec").arg(tool) } else { Command::new("npx").arg(tool) } } ``` ### Detection Order 1. **pnpm**: Check for `pnpm-lock.yaml` 2. **yarn**: Check for `yarn.lock` 3. **npm**: Default to `npx` ## Exit Code Preservation All commands preserve exit codes for CI/CD: ```bash theme={null} rtk lint || exit 1 rtk tsc || exit 1 rtk vitest run || exit 1 rtk playwright test || exit 1 ``` ## Token Savings Summary | Command | Standard Tokens | RTK Tokens | Savings | | - | - | - | - | | `eslint` (5 errors) | 500 | 80 | **-84%** | | `tsc` (5 errors) | 300 | 50 | **-83%** | | `next build` | 800 | 100 | **-87%** | | `prettier --check` (all pass) | 200 | 60 | **-70%** | | `vitest run` (24 pass) | 3,000 | 10 | **-99.5%** | | `playwright test` (2 fail, 22 pass) | 1,500 | 90 | **-94%** | | `prisma generate` | 500 | 60 | **-88%** | ## Next Steps > **[Python](/commands/python)** > > Python development tools > **[Go](/commands/go)** > > Go development tools This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.