pugjs/pug

Pug is a template engine for Node.js. A template engine lets you describe HTML in a shorter, easier-to-write form, fill in dynamic values like a user's name, and then have the engine produce the final HTML page. Pug is written in JavaScript and the README says it was heavily influenced by Haml, an older template engine from the Ruby world. The thing that stands out about Pug's syntax is that it is whitespace-sensitive: instead of writing closing tags, you express nesting by indenting child elements under their parent. The README shows a short example where you write a doctype and html tag, then head and body indented under it, and Pug expands that into a normal HTML page with all the angle brackets in the right places. The result is shorter, less visually noisy markup, and the syntax also supports variables, conditionals, and inline JavaScript. You install it from npm with npm install pug, and there is a separate pug-cli command-line tool for compiling .pug files into HTML or into JavaScript that can run in a browser. Pug runs in the browser too, though the README recommends pre-compiling templates rather than shipping the full compiler. The project was previously called Jade and was renamed at its 2.x release because Jade turned out to be a registered trademark, the older jade package name still works for existing apps. The README also lists ports of Pug to PHP, Java, Python, Ruby, and C# (ASP.NET Core), along with adapters for frameworks like Laravel, Symfony, Phalcon, and CodeIgniter.