JavaScript Validation¶
JavaScript and TypeScript projects face similar validation bottlenecks: ESLint runs for seconds, Prettier adds more time, and tsc on large codebases can take 30+ seconds. Agents that validate after every edit spend more time waiting than working.
Tool Execution Cost¶
| Tool | Traditional | Time |
|---|---|---|
| Linting | ESLint | 2-10s |
| Formatting | Prettier | 1-3s |
| Type checking | tsc | 10-60s |
Combined, a full validation pass can take 15-70 seconds. Run that 50 times per session and the agent spends more time blocked than coding.
Available Toolchains¶
Biome¶
Biome handles both linting and formatting at roughly 40x ESLint speed. One tool replaces ESLint and Prettier with a single config file and sub-second execution.
Knip¶
Knip finds unused files, dependencies, and exports. Dead code accumulates silently in growing codebases. Knip scans from entry points and reports anything that nothing imports. Run it at session boundaries to keep the codebase clean for both humans and agents.
TypeScript Compiler¶
tsc type-checks TypeScript code. A native port in development shows roughly 10x speedup.
Related Topics¶
- Validation Tools - Overview and hook patterns
- Hooks - PostToolUse triggers for validation