In this course, you will have an in-depth overview and the tools in your utility belt to write maintainable code in JavaScript. We will stick to the latest version of JavaScript in this course, ES2017. You don't have to know ES2017 to benefit from the course, as we will introduce the language constructs that we use during it. You will experience the benefits of functional programming even if your code is not purely functional. In this course, you will learn the building blocks that act as a utility belt in your arsenal, enabling you to write code that's easy to understand, extend, test, and debug. You will get hands-on practice on how to use currying, partial evaluation, map, reduce, filter, recursion, and other functional programming concepts in ES6.