Functions in JavaScript are like any other type; they can be passed around just like objects and primitive types. When we talk about most other values, however, we see that there is usually only one way to literally declare them. Object literals are declared using braces. Array literals are delimited square brackets. Functions, however, come in a variety of literal forms.

When outside of an object literal or class definition, you can declare a function in three different ways: as a function declaration, as a function expression, or as a fat-arrow function expression:

// Function Declarationfunction myFunction() {}// Function Expressionconst myFunction = function () {};// Named Function Expressionconst myFunction = function myFunction() ...

Get Clean Code in JavaScript now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.