Creating Scope Javascript

creating_scope_javascript.js

// How do we create scope?

function drive() {
  var innerState = 66;
  console.log(innerState); // Should print 66
}

drive(); //66

console.log(innerState); // Should print undefined or raise not defined
// Will print 66 when var is removed from innerState

// ------------------

// Functions create scope in JS. What happens when they're nested?

function processData(data) {
  data.forEach(processItem);
  
  function processItem(item) {
    var reversed = item.split("").reverse().join("");
    console.log(reversed);
  }
}

processData(["Apple", "Orange", "Pear"]);
// epplA, egnarO, reaP

processItem("Peach");
// processItem not defined

// -----------------------------

function processData(data) {
  var joinChar = "-"; // Works here
  data.forEach(processItem);
  
  function processItem(item) {
    // var joinChar = "-"; // Works here too
    var reversed = item.split("").reverse().join(joinChar);
    console.log(reversed);
  }
}

processData(["Apple", "Orange", "Pear"]);
// e-p-p-l-A, e-g-n-a-r-O, r-e-a-P

processItem("Peach");
// processItem still does not work