Clean Code in JavaScript

Function declarations

Function declarations are a type of hoisted declaration. A hoisted declaration is one that will, at runtime, be effectively hoisted up the top of its execution context, meaning that it will be immediately accessible to preceding lines of code (seemingly before it's declared):

hoistedDeclaration(); // => Does not throw an error...function hoistedDeclaration() {}

This, of course, is not possible with a function expression that's been assigned to a variable:

regularFunctionExpression();  // => Uncaught ReferenceError:  // => Cannot access 'regularFunctionExpression' before initializationconst regularFunctionExpression = function() {};

The hoisted behavior of function declarations can create unexpected results, so it is typically ...