@lanexio/parser-wasm

This page documents @lanexio/parser-wasm, the WASM bridge package that delegates to WASM-parsed grammar implementations. At v1.0, the WASM bridge is backed by pure TypeScript — WASM acceleration is a future optimization target.

• Version: Stable
• Module name: parser-wasm
• Package: @lanexio/parser-wasm
• Import path: @lanexio/parser-wasm
• Layer: 4 (Bridge)
• Runtime: Universal (requires WASM runtime support)
• Module format: ESM
• Stability: Stable
• Primary use case: WASM-backed parser bridge for HTML and Markdown.

Layer contract

Layer 4 dependency rules

This package depends on Layers 1 and 2. @lanexio/parser-wasm is universal but requires a WASM runtime. At v1.0, the WASM bridge is a pure-TS backed bridge.

When to use this module

• You want to use the WASM bridge interface for grammar parsing.
• You need to load bundled WASM bytes for HTML or toy grammar.
• You are building a custom integration that uses the WASM bridge pattern.

Module boundary

Boundary	Description
Inputs	Uint8Array (source bytes)
Outputs	LexTree
Side effects	WASM module instantiation on first use
Determinism	Yes
External dependencies	@lanexio/parser-core, @lanexio/parser-grammar-html, @lanexio/parser-grammar-markdown
Never-throw guarantee	Yes for parse functions. WASM instantiation may throw WasmLoaderError.
Security surface	None (delegates to grammar parsers)

Installation

1. Install the package.

   pnpm

   pnpm add @lanexio/parser-wasm

   npm

   npm install @lanexio/parser-wasm

   yarn

   yarn add @lanexio/parser-wasm

2. Import the named export.

   import { createHtmlWasmBridgeParser } from '@lanexio/parser-wasm';

Peer dependencies

Requirement	Required	Layer	Notes
@lanexio/parser-core	Yes	1	^1.0.0
@lanexio/parser-grammar-html	Yes	2	^1.0.0
@lanexio/parser-grammar-markdown	Yes	2	^1.0.0

Basic Usage

import { createHtmlWasmBridgeParser, parseHtml } from '@lanexio/parser-wasm';

const encoder = new TextEncoder();
const tree = parseHtml(encoder.encode('<p>Hello</p>'));

console.log(tree.nodeCount);

Create a WASM bridge parser

import { createHtmlWasmBridgeParser } from '@lanexio/parser-wasm';

const parser = createHtmlWasmBridgeParser();
const tree = parser.parse(encoder.encode('<p>Hello</p>'));

Exports

Export	Type	Description
createHtmlWasmBridgeParser	() => WasmBridgeParser	Create a WASM-backed HTML parser bridge.
createMarkdownWasmBridgeParser	() => WasmBridgeParser	Create a WASM-backed Markdown parser bridge (GFM enabled).
parseHtml	(bytes: Uint8Array) => LexTree	Parse HTML via WASM bridge.
parseMarkdown	(bytes: Uint8Array) => LexTree	Parse Markdown via WASM bridge.
createToyWasmBridgeParser	() => WasmBridgeParser	Create a WASM-backed toy grammar parser bridge.
loadBundledHtmlWasmBytes	() => Promise<Uint8Array>	Load bundled HTML WASM bytes.
loadBundledToyWasmBytes	() => Promise<Uint8Array>	Load bundled toy WASM bytes.
instantiateToyWasm	(bytes: Uint8Array) => ToyWasmParserExports	Instantiate toy WASM module from bytes.
createReferenceWasmBridgeParser	() => WasmBridgeParser	Create a reference WASM bridge parser.
WasmLoaderError	class	Error thrown when WASM instantiation fails.
WasmLoaderErrorCode	const object	Error code constants for WASM loader failures.
WasmFallbackError	class	Error thrown when WASM fallback is unavailable.
isWasmParserExports	(exports: unknown) => exports is WasmParserExports	Type guard for WASM parser exports.
isToyWasmParserExports	(exports: unknown) => exports is ToyWasmParserExports	Type guard for toy WASM parser exports.
TOY_GRAMMAR_NAME	string	Name of the toy grammar.
defineLanexioParserGrammar	(name: string, source: LanexioParserGrammarSource) => LanexioParserGrammar	Define a WASM grammar descriptor.
resolveGrammarSource	(source: LanexioParserGrammarSource) => Uint8Array | null	Resolve a grammar source to bytes.
toyGrammar	LanexioParserGrammar	Toy grammar descriptor.

Options

No options. All WASM bridge functions accept only Uint8Array.

Exported types

Type	Purpose	Notes
WasmBridgeParser	WASM bridge parser shape	{ runtime: string; parse: (bytes: Uint8Array) => LexTree }
WasmParserExports	WASM parser exports interface	Internal
ToyWasmParserExports	Toy WASM parser exports interface	Internal
LanexioParserGrammar	WASM grammar descriptor	Used for defining WASM grammars
LanexioParserGrammarSource	Grammar source (bytes, path, or URL)	Used for WASM grammar loading
LanexioParserGrammarSourceLike	Grammar source-like	Relaxed input type
WasmLoaderErrorCode	Error code type for WASM loader	Union of error codes

Configuration and Extension

WASM fallback

At v1.0, the WASM bridge is backed by pure TypeScript. WASM acceleration is a future optimization target. If WASM instantiation fails (WasmLoaderError), callers should fall back to the grammar-specific parse functions from @lanexio/parser-grammar-html or @lanexio/parser-grammar-markdown.

Accessibility

Accessibility requirements

• No direct accessibility surface. The WASM bridge delegates to grammar parsers.

Accessibility checklist

Concern	Status
Generated output semantics	Delegated to grammar parsers
ARIA attributes in serialized output	Not applicable
Semantic element round-trip	Not applicable

Security

Security considerations

• All parse functions never throw.
• WASM instantiation may throw WasmLoaderError if the WASM runtime is unavailable.

Threat	Mitigation	Status
Malformed input byte sequence	Delegates to grammar parsers (panic-free)	Implemented
WASM instantiation failure	Throws WasmLoaderError with clear message	Implemented

Companion packages

Package	Relationship	Layer	Notes
@lanexio/parser-core	Requires	1	Core tree and protocol
@lanexio/parser-grammar-html	Requires	2	HTML grammar delegation
@lanexio/parser-grammar-markdown	Requires	2	Markdown grammar delegation
@lanexio/parser	Consumes	6	Entry point uses WASM as optional backend
@lanexio/parser-pure	Fallback	4	Pure TS fallback when WASM unavailable

Changelog

Version	Date	Status	Notable changes
1.0.0	2026-05-29	Current	Initial stable release. Apache-2.0.

Migration notes

• None.

Related Content

Flat AST How the 16-byte node layout works.

Stability Guarantees Never-throw, panic-free, and 3-token recovery.