Chapter 5

Harnessing the Power of Functions


Bullet Getting to know JavaScript functions

Bullet Creating and using custom functions

Bullet Passing and returning function values

Bullet Working with anonymous and arrow functions

Bullet Getting to the bottom of variable scope

Bullet Understanding recursive functions

To iterate is human, to recurse divine.


As I demonstrate throughout this book, JavaScript comes with a huge number of built-in features that perform specific tasks. For example, something called the Math object has a built-in method for calculating the square root of a number. Similarly, a feature called the String object has a ready-made method for converting a string value to all lowercase letters.

Hundreds of these ready-to-roll features perform tasks that range from the indispensable to the obscure. But JavaScript can't possibly do everything that you’d like or need it to do. ...

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