Universal Module Definition

Definitions

1. A JavaScript module pattern (UMD) that wraps a module in a factory function with runtime checks to support multiple module systems — AMD (RequireJS), CommonJS (Node.js), and plain browser globals — from a single file. UMD was the standard way to ship libraries before ES modules became widely supported, and many legacy npm packages still use it.

   In plain English: A packaging format that lets a JavaScript library work in any environment — Node.js, old module loaders, or directly in a browser script tag.

   Example: "The library ships as UMD so it works whether you `require()` it in Node, load it with RequireJS, or just drop a `<script>` tag on the page."

Related Terms

• code splitting
• Export
• Tree Shaking
• Isomorphic
• Lexical Scope
• Prototype Chain
• Proxy Object
• Static Import
• Zone