Esbuild Plugin Peggy

🔌 Seamlessly load .pegjs or .peggy grammar files directly into your esbuild pipeline

✨ Features

• Compile .pegjs / .peggy files as ES modules with zero config
• Fully compatible with both JavaScript and TypeScript
• No Node.js-only dependencies get into your codebase — frontend safe!
• Supports custom parser options and per-file overrides
• Simple, fast, and modern integration with esbuild

📦 Installation

pnpm add esbuild-plugin-peggy

or

npm install esbuild-plugin-peggy

or

yarn add esbuild-plugin-peggy

🚀 Usage

// esbuild.config.ts
import { build } from "esbuild";
import { peggyPlugin } from "esbuild-plugin-peggy";

build({
  entryPoints: ["src/index.ts"],
  bundle: true,
  outfile: "dist/bundle.js",
  plugins: [peggyPlugin()],
});

Then in your source code:

import parser from "./grammar.pegjs";

const result = parser.parse("your input here");

⚙️ Plugin Options

You can pass either a global config or a list of per-file configs using ParserBuildOptions from peggy.

Global options

peggyPlugin({
  allowedStartRules: ["Expression"],
});

Per-file options

peggyPlugin([
  {
    pathPattern: /calculator\.pegjs$/,
    options: { allowedStartRules: ["Calc"] },
  },
]);

📁 Supported File Types

• .pegjs
• .peggy

🛠 Example

import parser from "./math.pegjs";

console.log(parser.parse("2 + 2")); // 4

✅ Why Use This?

• Skip manual parser builds — just import and use
• Compatible with modern tooling and frameworks
• Great for in-browser parsing and visual tooling
• Keeps frontend builds clean of Node-only deps

📜 License

Licensed under the MPL-2.0 license. © Mayank Chaudhari