- Explain event delegation
- Explain how
this
works in JavaScript
- Explain how prototypal inheritance works
- What do you think of AMD vs CommonJS?
- Explain why the following doesn't work as an IIFE:
function foo(){ }();
.
- What needs to be changed to properly make it an IIFE?
- What's the difference between a variable that is:
null
, undefined
or undeclared?
- How would you go about checking for any of these states?
- What is a closure, and how/why would you use one?
- Can you describe the main difference between a
forEach
loop and a .map()
loop and why you would pick one versus the other?
- What's a typical use case for anonymous functions?
- How do you organize your code? (module pattern, classical inheritance?)
- What's the difference between host objects and native objects?
- Difference between:
function Person(){}
, var person = Person()
, and var person = new Person()
?
- What's the difference between
.call
and .apply
?
- Explain
Function.prototype.bind
.
- What's the difference between feature detection, feature inference, and using the UA string?
- Explain Ajax in as much detail as possible.
- What are the advantages and disadvantages of using Ajax?
- Explain how JSONP works (and how it's not really Ajax).
- Have you ever used JavaScript templating?
- If so, what libraries have you used?
- Explain "hoisting".
- Describe event bubbling.
- Describe event capturing.
- What's the difference between an "attribute" and a "property"?
- 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 ===
?
- Explain the same-origin policy with regards to JavaScript.
- Make this work:
duplicate([1,2,3,4,5]); // [1,2,3,4,5,1,2,3,4,5]
- Why is it called a Ternary operator, what does the word "Ternary" indicate?
- What is
"use strict";
? what are the advantages and disadvantages to using it?
- Create a for loop that iterates up to
100
while outputting "fizz" at multiples of 3
, "buzz" at multiples of 5
and "fizzbuzz" at multiples of 3
and 5
- Why is it, in general, a good idea to leave the global scope of a website as-is and never touch it?
- Why would you use something like the
load
event? Does this event have disadvantages? Do you know any alternatives, and why would you use those?
- Explain what a single page app is and how to make one SEO-friendly.
- What is the extent of your experience with Promises and/or their polyfills?
- What are the pros and cons of using Promises instead of callbacks?
- What are some of the advantages/disadvantages of writing JavaScript code in a language that compiles to JavaScript?
- 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.
- What is event loop?
- What is the difference between call stack and task queue?
- 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
?
- What are the differences between ES6 class and ES5 function constructors?
- Can you offer a use case for the new arrow
=>
function syntax? How does this new syntax differ from other functions?
- What advantage is there for using the arrow syntax for a method in a constructor?
- What is the definition of a higher-order function?
- Can you give an example for destructuring an object or an array?
- ES6 Template Literals offer a lot of flexibility in generating strings, can you give an example?
- Can you give an example of a curry function and why this syntax offers an advantage?
- What are the benefits of using
spread syntax
and how is it different from rest syntax
?
- How can you share code between files?
- Why you might want to create static class members?