JS Questions:

• Explain event in JS and event delegation
• Explain how this works in JavaScript
• Explain how prototypal inheritance works
• Explain IFE
• What's the difference between a variable that is: null, undefined or undeclared?
• What is a closure, and how/why would you use one?
• What's the difference between .call and .apply?
• Explain Ajax .
• Have you ever used JavaScript templating?
  • If so, what libraries have you used?
• Explain "hoisting".
• Describe event bubbling.
• Why is extending built-in JavaScript objects not a good idea?
• Difference between window load event and document DOMContentLoaded event?
• What is the difference between == and ===?
• Ternary operator
• What is "use strict";
• Promises and Callback
• What tools and techniques do you use debugging JavaScript code?
• What language constructions do you use for iterating over object properties and array items?
• Explain the difference between mutable and immutable objects.
  • What is an example of an immutable object in JavaScript?
  • What are the pros and cons of immutability?
  • How can you achieve immutability in your own code?
• Explain the difference between synchronous and asynchronous functions.
• Explain the differences on the usage of foo between function foo() {} and var foo = function() {}
• What are the differences between variables created using let, var or const?
• Can you give an example for destructuring an object or an array?
• ES6 features
• DOM