This information is intended for the potential Front End Developer candidates. The following list includes a basic theoretical and code questions.
I hope, that my experience and experience of other developers will helps you to get the best interview results.

P.S. My main goal is to help candidates and to myself to get more web knowledge. Based on this point, let's improve the hard skills of Front-End community together. Please, send you Front-End interview questions via pull request.

1. Common interview questions
2. Common technical interview questions
3. HTML
4. CSS
5. Javascript
   • Junior candidate
   • Middle candidate
   • Senior candidate
6. Javascript Coding
7. React interview questions
8. Funny Questions
9. Contributing
   • Answers classification

1. What was the most interesting solution did you implemented at the last project?
2. What is the last book you read?
3. How big your team ever was?
4. Have you ever worked in Agile, Scrum or Kanban environments?
5. Which developers of Front End community do you know?
6. What do you hear about 'Gangs of four'?
7. Explain the difference between unit tests and integration tests? - @answer--stackoverflow
8. What are the most common types of web attacks do you know? - @answer--blog.sucuri.net
9. What is 'duck typing'? - @answer--wikipedia

1. What is REST? - @library--restcookbook
2. What is the difference between PUT and PATCH methods in REST? - @answer--stackoverflow
3. Tell about the differences between websockets, long polling and SSE. - @answer--stackoverflow
4. What is CORS? - @answer--maxcdn.com, @doc--mdn
5. List the main things you can do to increase page speed loading? - @answer--crazyegg.com
6. Progressive enhancement vs graceful degradation. What is the difference? - @answer--w3
7. Do you use Grunt, Gulp, Webpack or Browserify in your projects?
8. What do you know about "60fps"? What way to achieve this? - @answer--github
9. What is the difference between layout, painting and compositing? - @answer--google

1. Could you list main HTML5 tags? - @doc--mdn
2. What does mean optional closing tag? - @doc--w3
3. When and how to preload resources? - @answer--medium
4. What is different between id and class?

1. What is different between mobile first and desktop first - @answer--codemyviews.com?
2. Which of those selectors has the highest specificity. What color will be applied to the paragraph?
3. What pseudo-class :root refer to?
4. What preprocessor do you use (Sass, Less)?

1. Who is the author of JavaScript Language?
2. What is the best book for learning JavaScript? Why? - @answer-good-js-books--github
3. What type of NaN? How to check if a value is NaN?
4. What the reason that window.window === window return true? - @doc--mdn
5. What is the outcome of Javascript calculation? 1/0 = ?

1. What does this refer to? - @answer--javascriptissexy
2. What is the JavaScript Event Loop? - @answer--altitudelabs.com, @video-Roberts--youtube
3. What is the Event Delegation? - @answer--davidwalsh, @code-example
4. What is the difference between e.target and e.currentTarget? - @doc--mdn, @code-example
5. What is Window.postMessage() and where it can be used? - @doc--mdn
6. Is there any difference between Promises and callbacks? Which is better? - @answer-callback--callbackhell.com,
7. What is the recursion? When using of the recursion can be useful in Javascript? - @answer--medium

1. What patterns do you know and successfully use in JavaScript?
2. What is the different between Deferred and Promise objects? Where is Deferred object used?
3. What is the problem throttling and debouncing are resolved? What is the core difference between them? - @answer--medium

• Write a pipefy function where a string received is returned, but with the | character between each character. Make it possible to execute function in this way: 'javascript'.pipefy(). - @code-answer
• write a currying function that return sum of two numbers.
• Write a factorial function without side effect. @code

// Code below must return true
alert(factorial(3) === 6 && factorial(0) === 1);

• Which line of the below code will be executed with an error. Why?

10 .toString();
(10).toString();
10..toString();

• What is the order of alerts?

setTimeout(function(){
    alert('gorilla');
    setTimeout(function(){
        alert('classical inheritance')
    }, 0);
    alert('drumroll');
}, 0);

alert('banana');

• What is the result after code execution: 1, 2 or 3?

var x = 1;
var foo = {
  x:2,
  bar: function() {
    x = 3;
    return this.x;
  }
}
var run = foo.bar;

alert(run());

• What below code will return: true or false. What does each part of code return?

new String('a') instanceof String && 'b' instanceof String;

1. What happens when you execute setState() in the render() method?
2. What is the difference between 'smart and dummy' components?
3. How to create higher order component?
4. Tell about React in the SEO context.
5. Why rendering of React Components in the custom <div id="app"> is good practice than simple to the <body>?
6. What does mean "Isomorphic React Application"? - @answer--smashingmagazine

1. Do you like parties?
2. Do you know that we have a dress code?

Contributions, questions and comments, pull requests are all welcome.
Note: if you want to change a structure, please open an issue and we will discuss it, but if you have interesting questions or answers, please make pull request.

@answer-[tag]--[source tag] - General Theoretical Answer.
@doc-[tag]--[source tag] - Documentation
@library-[tag]--[source tag] - More Complex Answer
@code-[tag] - Code Example from jsfiddle || codepen || jsbin
@practice-[tag]--[source tag] - Good Practices
@video-[tag]--[source tag] - Video Materials