Javascript :: PBV v. PBR Functions

PbvV.PbrFunctions1.js

// Pass By Value vs. Pass By Reference
// callbacks: passing functions into other functions

function functionLogger(callback, argument) {     
  console.log('Function starting');
  const result = callback(argument);
  console.log('Functioncomplete');
  return result;
}

// writing a function using the expression method:

let happyFunction = function () {
    console.log("I am happy!");
}
happyFunction()    // <--- calling the function
>I am happy!

////////////////////////////
// calling functions stored in arrays
function happyFunction() {
    console.log('I am happy!');
}
let amazingArray = [happyFunction, happyFunction, happyFunction];

for (let i = 0; i < amazingArray.length; i++) {
    let element = amazingArray[i];
    element();
}
>I am happy!
 I am happy!
 I am happy!
 
 
////////////////////////////

// you can pass in a function as a parameter into another function
function firstFunction(anotherFunction) {
    anotherFunction(); // invoke a function
}



function saysHi(name) {
    console.log('Hi', name);
}

function saysBye(name) {
    console.log('Bye', name);
}

function callsWithName(name, sayHiOrBye) {
    sayHiOrBye(name);
}

callsWithName('Sadie', sayssHi);
callsWithName('Sadie', saysBye);
>Hi Sadie
>Bye Sadie


// passing in an anonymous function when you don't need a name, just instructions
// the second parameter passed is the entire function
sayToAll(group, function (name) {
    console.log("Hello, " + name + "!");
})


// callback example
function finderFunction(anArr, callback) {
  for (let i=0; i < anArr.length; i++) {
    let currElem = anArr[i];
    if (callback(currElem)) return i;
  }
  return -1;
}