callbackScratch.js

function takesACallBack(something, callback) {
 
  callback(something);
  
}


function logger(argument) {
  
  console.log(argument);
  
}

logger("hello world");

takesACallBack("hello world", function(arg) {
  
  console.log(arg);
  
});




// performsMath takes in a Number for a and b
// take a callback function for callback 
// the callback functions arguments are two numbers

// Function to perform math on each passed in argument
// Invoked with arguments (firstNumber, secondNumber). Return result of mathematical function



function performsMath(a, b, callback) {
    
    if(typeof callback !== 'function') {
        throw Error("callback must be a function")
    }
  
  console.log(callback(a, b));
  
}


function add(first, second) {
    
    return first + second;
    
}

function divide(first, second) {
    return first / second;
}

function subtract(first, second) {
    
    return first - second;
    
}

function multiply(first, second) {
    
    return first * second;
    
}

performsMath(5,2, multiply);