Great job! By thinking about functions as data and learning about higher-order functions, you’ve taken important steps in being able to write clean, modular code and take advantage of JavaScript’s flexibility.

Let’s review what we learned in this lesson:

• Abstraction allows us to write complicated code in a way that’s easy to reuse, debug, and understand for human readers

• We can work with functions the same way we would any other type of data including reassigning them to new variables

• JavaScript functions are first-class objects, so they have properties and methods like any object

• Functions can be passed into other functions as parameters

• A higher-order function is a function that either accepts functions as parameters, returns a function, or both