Call stack notes

The call stack: 
    Array with two methods:
    first in last out. 
        push()
        pop()
        peak() //looks at the first one. 

Callback queue 
    first in, first out. 
    runs by adding them to the call stack
    basically an array, with two special methods:
        enqueue (unshift())
        dequeue (shift())

Hoisting variables is done to make sure everything is declared before adding to the call stack. 

this[this.length++] = value //increments after evaluation 
this[++this.length} = value //increments before evaluation