Scopes

Global scope

• Variables defined outside of a function are in the global scope
• Global scope lives as long as your application lives
• Variables in the global scope can be accessed from everywhere on the application

Local scope

• Variables defined inside a function are in local scope
• Local Scope lives as long as your functions are called and executed
• Each function when invoked creates a new scope

Lexical scope

Lexical Scope means that in a nested function (function within a function), the inner functions have access to the variables and resources of their parent function.

function outer() {
  let a = 323;
  function inner() {
    console.log(a);
  }
  inner()
}
outer();

Inner functions can access variables from their parent scope due to lexical scoping.