Node's `constants` module for the browser

 This modules provides constants present in a Node.js environment to code
 running in a browser.
 .
 This library is a dependency for browserify and webpack. Browserify/Webpack
 takes code targeted at node.js and makes it run in the browser. Node.js comes
 with API of its own that is not available in the browsers. Browserify/Webpack
 exposes this code to programs that are unaware they are running in a browser.
 .
 Node.js is an event-based server-side JavaScript engine.