function_expression.js

// function sum(a, b) {
//     return a + b;
//  }
// let v = sum(99, 1);
// console.log(v);

var x = function sum(a, b) {
    return a + b;
  } // x is a function
  // the reason x is a function is because it is a 
  // variable that is assigned to a function
  
  // these are called function expressions
  // because the function is assigned to a variable
  // and the variable can be used as a function

  let v = x(99, 1);
  console.log(v);