Clean Code in JavaScript

Syntactic context

There are three syntactic contexts in which a function can exist:

• As a statement
• As an expression
• As a method definition

Statements can be thought of as the scaffolding. For example, const X = 123 is a Statement that contains a const declaration and assignment. Expressions can be thought of as the values that you place into the scaffolding; for example, 123 in the latter statement is an expression. In Chapter 9, Parts of Syntax and Scope, we'll talk about this topic in more detail.

The difference between functions as statements and functions as expressions is exemplified by the function expression and the function declaration. The function declaration is quite unique in that it is the only way to declare a function that ...