@sylphx/synth-wasm-js

High-performance JavaScript/TypeScript parser compiled to WebAssembly.

Features

• ES2024 syntax - Full support for modern JavaScript
• Fast - 175 MB/s throughput, ~7μs per KB
• Compact - 48KB WASM binary
• Zero dependencies - Just the WASM module

Installation

bun add @sylphx/synth-wasm-js

Usage

import { parse, parseCount, parseBinary, NodeKind } from '@sylphx/synth-wasm-js'

// Parse to structured AST
const result = await parse('const x = 1;')
console.log(result.nodes) // Array of ASTNode

// Quick node count (for validation)
const count = await parseCount('function foo() {}')
console.log(count) // 5

// Maximum performance (raw binary)
const binary = await parseBinary('class Foo {}')

API

parse(source: string): Promise<ParseResult>

Parse JavaScript and return a structured AST.

const result = await parse('const x = 1 + 2;')

// result.nodes is an array of ASTNode:
// - kind: NodeKind (Program, VariableDeclaration, etc.)
// - flags: node flags (const, let, async, etc.)
// - start: source start offset
// - end: source end offset
// - extra: additional data (e.g., child count)

parseBinary(source: string): Promise<Uint8Array>

Parse to compact binary format for maximum performance.

Binary format:

• Header: [node_count: u32]
• Nodes: 16 bytes each (kind: u8, flags: u8, pad: u16, start: u32, end: u32, extra: u32)

parseCount(source: string): Promise<number>

Returns only the node count. Useful for benchmarking.

tokenize(source: string): Promise<number>

Returns token count. Useful for benchmarking the lexer.

Supported Syntax

• Declarations: const, let, var, function, class, import, export
• Statements: if, for, for-in, for-of, while, do-while, switch, try/catch/finally, return, throw, break, continue
• Expressions: Binary, unary, call, member, new, arrow functions, async/await, yield, template literals, object/array literals, spread, optional chaining, nullish coalescing
• Patterns: Array destructuring, object destructuring, rest elements

Performance

| Metric | Value | |--------|-------| | Throughput | 175 MB/s | | Per 1KB parse | ~7μs | | WASM size | 48KB |

Credits

Built with Rust and wasm-bindgen.

License

MIT