What is 'hoisting' in JavaScript?

What is 'hoisting' in JavaScript?
Hoisting is a JavaScript mechanism where variables and function declarations are moved to the top of their containing scope during the compile phase, before the code has been executed. It's important to note that only the declarations are hoisted, not initializations. If a variable is declared and initialized after using it, the value will be undefined. Understanding hoisting is important as it helps to avoid bugs related to order of operations in your code.