Great job! By thinking about functions as data, and learning about higher-order functions, you’ve taken important steps in learning to write clean, modular code that takes 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 work with 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 other 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.
Instructions
Feel free to play around with the code in the workspace.
- What happens if you change the value of
2incheckA? - Which variable holds the callback function?
- What happens if you invoke the function’s argument?
In the following lesson, you’ll learn how higher-order functions are used in some of the most important and widely-used JavaScript methods, iterators!