console.clear();


/***** Var *****/
console.log( '***** Var *****');

// Global scope available to functions
var globalName = 'World';

function greet() {
  // Declared inside the greet() function
  var myName = globalName;
  console.log( 'Hello ' + myName );
  
  
  if ( myName === 'World' ) {
    var myOtherName = 'Sacramento';
  }
  
  // myOtherName is available outside of the if statement
  console.log( 'Hello ' + myOtherName );
  
}
greet();
// This will both error out because the variables are not defined outside of the function
// This will throw an error and terminate everything after it
// console.log( 'Hello ' + myName );
// console.log( 'Hello ' + myOtherName );



/***** const *****/
console.log( '***** Const *****');


function one() {
  const a = 1;
  // This would throw an error
  // Can't redefine constants inside a block
  // a = 2;
  
  console.log( a );
  
  if ( a === 1 ) {
    // You still can't reassign it, as its value is inherited.
    // This will throw an error
    // a = 2;
    
    // However, inside a block you can declare a new constant with the same name. 
    // This constant is scoped to just the if statement block
    const a = 2;
    // The value of a here is 2
    console.log( a );
  }

  // Outside the if block, the value remains 1
  console.log( a );
}
one();
// It doesn't exist here because it was declared inside the function one()
// This will throw an error and terminate everything after it
// console.log( a );



/**** let *****/
console.log( '***** Let *****');


function two() {
  let x = 1;
  // It's safe to reassign variables declared with let
  x = 2;
  
  // The value is 2
  console.log( x );
  
  if ( x === 2 ) {
    // Inside a block you can redeclare it
    // This is only scoped to the if statement
    let x = 3;
    // The value here is 3
    console.log( x );
  }

  // Outside the if block, the value remains 2
  console.log( x );
}
two();
// It doesn't exist here because it was declared inside the function one()
// console.log( x );