NEA - scope.md

Scopes Discussion

1. What is the scope of variable GLOBAL_DATA in the example below:

<script>
  let GLOBAL_DATA = { value : 1};
</script>

Pretend in the console, that we type: console.log(GLOBAL_DATA);

2. What is the scope of variable x in the examples below:

let x = 1;
{ 
  let x = 2;
}
console.log(x);
var x = 1;
{ 
  var x = 2;
}
console.log(x);

3. What is the scope of variable x in the examples below:

function outerFn(){
    let x = 1;
    function log(){
      console.log(x);
    };
    function run(fn){
      let x = 100;
      fn();
    }
    run(log);
};
outerFn();

4. What do we call this method of scoping:

let x0 = 0;
function fn1(){
  let x1 = 1;
  fn2();
  function fn2(){
    let x2 = 2;
    fn3();
    function fn3(){
      let x3 = 3;
      console.log(x0 + " " + x1 + " " + x2 + " " + x3);
    };
  };
};
fn1();

5. What is the difference between global scope and other scope types and when do we use the global scope?

6. What is the difference between let and var defining a variable?

7. What is the difference between strict mode and sloppy mode?