Difference between declarations

Both ways of declaring a function are equivalent, but there is a significant difference: functions declared as Function Declaration will be available even if they are accessed before they were declared.

See an example:

javascript// Calling a function before it is declared:
func(); // shows '!'

function func() {
  console.log('!');
}

And Function Expressions are created at the time of code execution and are not available above. So this code will throw an error:

javascriptfunc(); // error, there is no such function yet!

let func = function() {
  console.log('!');
};