what are callbacks
/*
tl;dr: Callbacks are a way to force one function to complete,
before running another. Used for asynchronus programming.
*/
// Consider this example:
names = ['Anthony', 'Betty', 'Camie']
function addName(name, callback){
setTimeout(function(){
names.append(name)
callback()
}, 200)
}
function getNames(){
setTimeout(function(){
console.log(names)
}, 100)
}
addName('Daniel', getNames)
/*
addName('Daniel', getNames) is saying:
'finish the function addName() BEFORE running the function getNames()'
> 'getNames()' here is the callback
Without the call back in this example, getNames would finish
before addName. (setTimeout is used to force one function to go slower)
Callbacks are given as arguments to other functions
*/