Luna Benchmark Report

Comparison benchmark results: Luna vs React vs Preact.

TL;DR - Luna's Strengths

Bundle Size Comparison

Luna is 1/6 the size of React. Larger than Preact, but includes Signal, SSR, and Island Architecture as a full-stack framework.

Runtime Performance

Benchmark results in jsdom environment (vitest bench).

Initial Mount (2,500 cells)

Reactive State Mount (2,500 cells)

State Update (2,500 cells)

Note: Preact's extremely fast update may be due to state change batching.

Large Grid (5,000 cells)

List Operations (Add 100 items)

Analysis

Current Status

Luna is currently slower than React/Preact in raw speed. This is due to:

1. MoonBit → JS compilation: Generated JS code has room for optimization compared to hand-written code

2. Fine-Grained Reactivity overhead: Dependency tracking cost per element

3. Early development stage: Optimization work is still in progress

Luna's Value Proposition

Speed isn't everything. Luna provides these values:

Future Optimization Opportunities

1. wasm-gc target: MoonBit can compile to wasm-gc, potentially faster than JS in the future

2. Compiler optimization: Automatic speedup through MoonBit compiler improvements

3. DOM operation optimization: Current implementation has room for improvement

Benchmark Environment

• Node.js v24 + jsdom

• Vitest 4.0.15

• macOS Darwin 24.5.0

Running Benchmarks

cd luna.mbt
npx vitest bench js/luna/benches/grid.bench.ts --run

Luna's Strengths - MoonBit Benchmarks

Internal MoonBit benchmark results for Luna. These demonstrate Luna's architectural strengths.

SSR (Server-Side Rendering)

SSR performance is extremely fast - Can generate a 1000-element list in 78µs.

Signal (Fine-Grained Reactivity)

Signal updates at 11M ops/sec - Orders of magnitude faster than React's setState.

DOM Updates (Fine-Grained)

Partial updates at 4.5M ops/sec - Direct DOM updates without VDOM diffing.

Why Luna is Slower in VDOM Benchmarks

Luna is slower than Preact in grid benchmarks (updating all 2,500 cells), because:

1. Full element updates are not Luna's target use case

   • Fine-Grained Reactivity assumes "update only parts"

   • Updating all 2,500 cells every time suits VDOM

2. Luna's design philosophy

   • Only changed Signals update the DOM

   • 1 cell update = 0.22µs (no VDOM diff needed)

3. In real apps, Luna excels when

   • Most UIs involve partial updates

   • Island Architecture distributes initialization cost

Conclusion

When Luna is a Good Fit

• ✅ Need SSR + selective hydration

• ✅ Want Island Architecture for partial hydration

• ✅ Frequent partial updates (reactive dashboards, etc.)

• ✅ Small bundle size matters (1/6 of React)

• ✅ Want type-safe UI with MoonBit

• ✅ Looking ahead to wasm-gc support

When Luna is Not a Good Fit

• ❌ Mass element updates (game frame updates, etc.)

• ❌ Need React/Preact ecosystem (existing libraries)

Comparison Summary