Scope

Q: What will be printed on the console?

(function () {
  var a = (b = 5);
})();

console.log(b); // $: 5

• variable a is declared using the keyword var as local function variable
• b is not defined using var and is assigned to the global scope
• doesn't use strict mode ('use strict';) inside the function
  • strict mode requires you to explicitly reference to the global scope
    • var a = window.b = 5;

(function () {
  'use strict';
  var a = (b = 5);
})();

console.log(b); // $: Uncaught ReferenceError: b is not defined