Symbol.metadata Polyfill

@tsmetadata/polyfill provides the necessary polyfill for legacy runtimes to properly use decorator metadata in TypeScript 5.2+.

In addition, the library provides the necessary global type declaration for Symbol.metadata.

• 🌱 Install
• ⚙️ Usage
• 🙏 Thanks

🌱 Install

npm install @tsmetadata/polyfill

⚙️ Usage

As early as possible, import the polyfill.

import '@tsmetadata/polyfill';

After doing so, Symbol.metadata will be defined.

You may also need to configure your tsconfig.json to target <= ES2022 and include the esnext.decorators library. The easiest way to do this is to extend our included polyfill-ready configuration.

{
  "$schema": "https://json.schemastore.org/tsconfig",
  "extends": ["@tsmetadata/polyfill/lib/tsconfig.polyfill.json"],
}

🙏 Thanks

Special thanks to Oleksandr Tarasiuk for implementing decorator metadata and to Andrew Branch for releasing an early version of this polyfill.