UMD, or Universal Module Definition, is a module definition format that aims to be compatible with both CommonJS and AMD. It also allows you to export the module as a global variable that you can include in your application through a simple <script> tag.
It does this by wrapping the modules in a boilerplate that checks the environment to detect how the module is used, and produces the correct exported object.
For example, the preceding greeter example would look like this with UMD:
// greeter.js(function (root, factory) { // Requirements are defined here}(this, function () { function helloWorld(name) { process.stdout.write(`hello ${name}!\n` }; // Whatever you return is exposed return { helloWorld: helloWorld
