functions_Scope_lab

//Function Scope lab
//scope determined by where variable is defined
//global or local
//scope chain
//"use strict" mode


//practice
function roadTrip(){
    var gallons = 12;
    var mpg = 34;             //milles per gallon
    return gallons * mpg;
}

roadTrip();

//challenge
//scope chain
//local scope >> parent scope >> grandparent scope >> etc.. >> global scope >> error
//get a local value for a function

//bad practice
function roadTrip2(){
    gallons2 = 10;
    mpg2 = 34;
    return gallons2 * mpg2;
}

roadTrip2();

//better practice
var gallons3 = 11;
var mpg3 = 25;
function roadTrip3(){
    return gallons3 * mpg3;
}

roadTrip3();

//best practice
// "use strict" example in the console with the IIFE - Immediately Inovked Function Expressions\
(function(){
    //"use strict"; - this cause an error
    food = "pizza";
}());



//challenge
//build a nested function (zagnieżdżona)
//child scope >> parent scope >> global scope
//run the resuld of the child scope
//1)go from the child scope and grab the value from the parent scope
//2)then go for the another value from the global scope

var carName = "mercedes";

(function(answer){
    var sport = function(year,fuel){
    fuel = "petrol";
    year = 2001;
    return "My car is " + carName + " " + answer + " build in " + year + " with " + fuel + " engine";
    }
    var year = 2001;
    return sport();
}("sport"));

//lesson solution

//global scope
var height = 10;

function volume(){
//parent scope
var width = 10;
var lenght = 10;
var volumeOfObject = function(){
//child of local scope
return lenght * width * height;
}    
//return value of function expression volumeOfObject
return volumeOfObject();
}