pegjs-loader's Introduction

PEG.js loader for webpack

Install

npm install --save-dev pegjs-loader pegjs webpack

The pegjs-loader requires PEG.js and webpack as peerDependency. Thus you are able to specify the required versions accurately.

Usage

Documentation: Using loaders

var parser = require("!pegjs!./parser.pegjs");
// => returns compiled PEG.js parser

Apply via webpack config

It's recommended to adjust your webpack.config so pegjs! is applied automatically on all files ending with .pegjs:

module.exports = {
  ...
  module: {
    loaders: [
      {
        test: /\.pegjs$/,
        loader: 'pegjs-loader'
      }
    ]
  }
};

Then you only need to write: require("./parser.pegjs").

PEG.js options

You can pass options to PEG.js as query parameters. The following options are supported:

cache — if true, makes the parser cache results, avoiding exponential parsing time in pathological cases but making the parser slower (default: false)
optimize - whether to optimize the built parser either for speed or size (default: speed)
allowedStartRules - The rules the built parser will be allowed to start parsing from (default: the first rule in the grammar).
trace - if true, the tracing support in the built parser is enabled (default: false)

module.exports = {
  ...
  module: {
    loaders: [
      {
        test: /\.pegjs$/,
        loader: 'pegjs-loader?cache=true&optimize=size&allowedStartRules[]=RuleA,allowedStartRules[]=RuleB&trace=false'
      }
    ]
  }
};