It’s important to remember that hoisting is related to how the compiler reads through a program and that it doesn't literally alter the code. You’ll learn how and why they work, and how an understanding of closures can be a powerful part of your development skillset. The snippet below shows the sequence in which the elements in the code above would be read by the compiler, resulting in the impression of being hoisted/lifted. This concise yet in-depth guide takes you inside scope and closures, two core concepts you need to know to become a more efficient and effective JavaScript programmer. Therefore it feels like these elements are hoisted/lifted to the top of their scope so that the program is aware of them beforehand. Hoisting is achieved by allocating memory locations for the variable declarations, class declarations, and function declarations in your code when compiling.

It seems that the program is somehow aware of these elements in the code that are yet to be defined. It simply prints undefined in the console. youdontknowjs is a very popular javascript book series written by Kyle Simpson.-Figured today let’s do a one minute quick review Shall weSo here. But still, if you run the code, you'll notice that the program doesn't throw any errors. No matter how much experience you have with JavaScript, odds are you don’t fully understand the language. Here you can see that the printVariable function is called before it's defined, and the variable passed into the function is also used before it’s defined.

You dont know js hoisting