lezer-loader

library0.3.0jsnpmunverified

A webpack loader for Lezer grammar files (.grammar). Currently at version 0.3.0 with a stable API. It enables importing .grammar files as parser modules, supporting external token imports. No configuration options are supported yet. @external imports in grammar files are not tracked as webpack dependencies, requiring manual rebuild triggers. Best paired with @lezer/generator and @lezer/lr for TypeScript usage.

serialization devops

npm install lezer-loader

github ↗package ↗

INSTALL

IMPORT

SIG · LEZER-LOADER

lezer-loader

serializationjavascriptv0.3.0

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default (parser)

✓ import parser from './syntax.grammar'

✗ const parser = require('./syntax.grammar')

Default export is the LRParser instance. Use ESM syntax for webpack.

named (external tokens)

✓ import { insertSemi } from './syntax.grammar'

Named exports only exist for external tokens defined in the grammar with @external tokens.

type (TypeScript)

✓ import type { LRParser } from '@lezer/lr'

✗ import { LRParser } from '@lezer/lr'

Use type-only imports for TypeScript declarations to avoid runtime overhead.

Configures webpack to handle .grammar files with lezer-loader, enabling import of Lezer parsers.

// webpack.config.js module.exports = { module: { rules: [ { test: /\.grammar$/, use: 'lezer-loader', }, ], }, };

Debug

Known issues

gotcha@external imports in grammar files are not tracked as webpack dependencies. Edit the grammar file to trigger a rebuild.

fix

Manually edit the .grammar file (e.g., add a comment or change whitespace) to force webpack to recompile.

affects: >=0.0.0

breakingNo options are supported yet. Attempting to pass options to the loader may break silently.

fix

Do not pass any options to the loader in webpack config.

affects: ==0.3.0

Errors

Common errors & fixes

Module parse failed: Unexpected token (1:0) in file.grammar

Webpack is not configured to handle .grammar files with lezer-loader.

fix

Add rule { test: /\.grammar$/, use: 'lezer-loader' } to webpack config.

Cannot find module './tokens' from 'syntax.grammar'

External token import path is incorrect or tokens.js is not in webpack's resolution scope.

fix

Ensure the @external tokens import path in the grammar file is correct and the module is accessible.

Upgrade

Version history

0.3.0latest on npm

Audit

Dependencies

@lezer/generatoroptionalPeer dependency required for grammar generation

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/jared-hughes/lezer-loader ↗

packagehttps://www.npmjs.com/package/lezer-loader ↗