{"id":811,"date":"2018-10-02T00:45:48","date_gmt":"2018-10-02T00:45:48","guid":{"rendered":"https:\/\/blog.hassler.ec\/wp\/?p=811"},"modified":"2018-09-26T01:03:32","modified_gmt":"2018-09-26T01:03:32","slug":"10-javascript-concepts-you-need-to-know-for-interviews","status":"publish","type":"post","link":"https:\/\/blog.hassler.ec\/wp\/2018\/10\/02\/10-javascript-concepts-you-need-to-know-for-interviews\/","title":{"rendered":"10 JavaScript concepts you need to know for interviews"},"content":{"rendered":"
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Self-Learning<\/h3>\n

There are thousands of self-taught JavaScript programmers looking for web development positions. Unfortunately, self-learning often leaves gaps in people\u2019s understanding of the language itself.<\/p>\n

It\u2019s surprising how little JavaScript one needs to make complex web pages. Often, people who can create entire sites lack knowledge of the language\u2019s fundamentals.<\/p>\n

It\u2019s rather easy to avoid the complex topics and implement features using basic skills. It\u2019s also easy to create a website by relying on Stack Overflow, without understanding the code being copied.<\/p>\n

If you\u2019re looking to improve your JavaScript interview skills, check out<\/strong>Master the JavaScript Interview<\/strong><\/a><\/p><\/blockquote>\n

Interviews<\/h3>\n

The problem is that questions testing your understanding of JS are exactly what many tech companies ask in their interviews. It\u2019s clear when an applicant knows enough to scrape by, but lacks a solid grasp of the language.<\/p>\n

Here are concepts that are frequently asked about in web development interviews. This is assuming you already know the basics such as loops, functions, and callbacks.<\/p>\n

Concepts<\/h3>\n
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  1. Value vs. Reference<\/a>\u200a\u2014\u200aUnderstand how objects, arrays, and functions are copied and passed into functions. Know that the reference is what\u2019s being copied. Understand that primitives are copied and passed by copying the value.<\/li>\n
  2. Scope<\/a>\u200a\u2014\u200aUnderstand the difference between global scope, function scope, and block scope. Understand which variables are available where. Know how the JavaScript engine performs variable lookup.<\/li>\n
  3. Hoisting<\/a>\u200a\u2014\u200aUnderstand that variable and function declarations are hoisted to the top of their available scope. Understand that function expressions are not hoisted.<\/li>\n
  4. Closures<\/a>\u200a\u2014\u200aKnow that a function retains access to the scope that it was created in. Know what this enables us to do with our code. Understand that closures allow data hiding, memoization, and dynamic function generation.<\/li>\n
  5. this<\/a><\/code>\u200a\u2014\u200aKnow the rules of\u00a0this<\/code>\u00a0binding. Know how it works, know how to figure out what it will be equal to in any piece of code, and know why it\u2019s useful.<\/li>\n
  6. new<\/a><\/code>\u200a\u2014\u200aKnow how it relates to object oriented programming. Know what happens to a function called with\u00a0new<\/code>\u00a0and why such a function is known as a constructor. Understand that an object generated by using\u00a0new<\/code>inherits<\/em>\u00a0from the function\u2019s prototype property.<\/li>\n
  7. apply<\/a><\/code>,\u00a0<\/a>call<\/a><\/code>,\u00a0<\/a>bind<\/a><\/code>\u200a\u2014\u200aKnow how each of these functions work. Know how to use them. Know what they do to\u00a0this<\/code>.<\/li>\n
  8. Prototypes & Inheritance<\/a>\u200a\u2014\u200aUnderstand that inheritance in JavaScript works through the\u00a0[[Prototype]]<\/code>\u00a0chain. Understand how to set up inheritance through functions and objects and how\u00a0new<\/code>\u00a0helps us implement it. Know what the\u00a0__proto__<\/code>\u00a0and\u00a0prototype<\/code>\u00a0properties are and what they do.<\/li>\n
  9. Asynchronous JS<\/a>\u200a\u2014\u200aUnderstand the event loop. Understand how the browser deals with user input, web requests, and events in general. Know how to recognize and write asynchronous code. Understand how JavaScript is both asynchronous and single-threaded.<\/li>\n
  10. Higher Order Functions<\/a>\u200a\u2014\u200aUnderstand that functions are first-class objects in JavaScript and what that means. Know that returning a function from another function is perfectly legal. Understand the techniques that closures and higher order functions allow us to use.<\/li>\n<\/ol>\n

    More Resources<\/h3>\n

    If the links included aren\u2019t enough, there are countless resources out there to help you learn these concepts.<\/p>\n

    I personally created\u00a0Step Up Your JS<\/a>\u00a0to help people get experience with these topics. It covers all of these concepts and more.<\/p>\n

    Here are other resources which I\u2019ve read or watched at least some of and can recommend.<\/p>\n