Do you know what will be the output of this code? console.log(greet()); var greet = function () { return "hi"; };

Why can't you call a function expression before it's defined?

Do you know what will be the output of this code?

JavaScript

console.log(greet());

var greet = function () {
  return "hi";
};

Show answer and explanation

The answer is TypeError: greet is not a function.

var greet is hoisted and set to undefined. The function is only assigned when that line runs. Calling undefined() throws a TypeError.