Difference between a function expression and a function declaration in JavaScript?

 In JavaScript, a function expression defines a function as a part of a larger expression, such as a variable assignment, while a function declaration defines a function as a standalone statement.

Here is an example of a function expression:

let add = function(a, b) {
  return a + b;
};

And here is an example of a function declaration:

function subtract(a, b) {
  return a - b;
}

One key difference between function expressions and function declarations is that function expressions can be anonymous, while function declarations must have a name. Another difference is that function declaration are hoisted to the top of their scope, meaning that they can be called before they are defined, while function expressions are not hoisted and must be defined before they are called.

I hope this helps! Let me know if you have any other questions.