6to5 turns ES6 code into vanilla ES5, so you can use ES6 features today. Fast - no redundant code added so your compiled code is as fast as possible. Extensible - with a large range of plugins. Lossless - source map support so you can debug your compiled code with ease. Compact - maps directly to the equivalent ES5 with no runtime. Concise - does not pollute scope with unneccesary variables.