# TJS Benchmarks Generated: 2026-08-19 Runtime: Bun 1.3.14 Platform: darwin arm64 Iterations: 100,000 per test ## Summary | Benchmark | Baseline | Safe (default) | Unsafe (!) | | ------------------------------------- | -------- | -------------- | ------------- | | CLI: Bun + TypeScript | 45.5ms | - | - | | CLI: tjsx (execute TJS) | 41.3ms | - | - | | CLI: tjs emit | 42.8ms | - | - | | CLI: tjs check | 43.1ms | - | - | | Simple arithmetic (100K iterations) | 0.4ms | 0.6ms (1.5x) | 0.4ms (~1.0x) | | Object manipulation (100K iterations) | 0.4ms | 0.7ms (1.7x) | 0.5ms (1.1x) | | 3-function chain (100K iterations) | 0.4ms | 0.8ms (2.0x) | 0.4ms (0.9x) | ## Key Findings ### CLI Cold Start - **Bun + TypeScript**: ~46ms (native, baseline) - **tjsx**: ~41ms (includes TJS transpiler load) - **Overhead**: none measurable — `tjsx` starts as fast as plain Bun Loading the acorn parser and the TJS transpiler costs less than the run-to-run spread of this measurement, so it does not show up as startup cost. ### Safe vs Unsafe Functions TJS functions are **safe by default** with runtime type validation. Use `(!)` to mark functions as unsafe for performance-critical code: ```javascript // Safe (default) - validates types at runtime function add(a: 0, b: 0): 0 { return a + b } // Unsafe - no validation, maximum performance function fastAdd(! a: 0, b: 0): 0 { return a + b } ``` Performance comparison: - Simple arithmetic: Safe 1.5x vs Unsafe ~1.0x - Object manipulation: Safe 1.7x vs Unsafe 1.1x - 3-function chain: Safe 2.0x vs Unsafe 0.9x ## Recommendations 1. **Use safe functions at API boundaries** - The default is correct for most code 2. **Use `(!)` for internal hot paths** - When inputs are already validated 3. **Consider compiled binary for CLI** - `bun build --compile` for ~20ms startup ## Running Benchmarks ```bash bun run bench ``` Or run the test suite with timing output: ```bash bun test src/lang/perf.test.ts ```