Meta Frontend Engineer Interview Guide

The phone screening is designed to evaluate your technical skills and experience in developing and maintaining Frontend applications. The interviewer will briefly go over your resume and ask if you have any questions. The interviewer will ask you technical questions related to Frontend development mostly emphasizing on your experience in Javascript.

• Imagine it’s your first day here at Meta. What do you want to work on? What 
• features would you improve on?
• Why are you interested in Meta? Know about our technical environment, projects, challenges, etc. Your excitement about Meta will go a long way.
• What are the most interesting projects you’ve worked on? How are they relevant to the Meta environment?
• What are some of the biggest professional challenges you’ve faced, and how have you overcome them?

The second primary interview is a technical screening that focuses on your problem-solving abilities, core computer science skills, and ability to build practical applications. You will be interviewed by a senior Frontend Engineer at Meta, who will ask you a series of technical questions related to JavaScript, HTML, and CSS.

You will be expected to write code in JavaScript, and focus primarily on getting to a working solution. It is also important to provide a narrative as you work so that the interviewer can gain insight into your thought process.

Some of the topics that may be covered during the interview include algorithms, data structures, design patterns, recursion, graph/tree traversal, and relative performance of JavaScript object and array operations. The interviewer will also expect you to be proficient in JavaScript language and its primitives, including iteration, closures, scope, and writing asynchronous code. Additionally, it will be helpful to recap data structures common in UI engineering like arrays, maps, sets, and DOM trees and understand computer science topics like Big O notation and tree traversal.

• For a recursive description of DOM elements i.e. var dom = { type:'div', props:{id:'hello', children:[{type:'h1', children:'HELLO'}]}}. Define a function that prepares actual DOM elements.
• Can you walk me through your thought process when approaching a coding problem?
• Explain the difference between null and undefined in JavaScript.
• How would you implement a function that determines if a given word is a palindrome in JavaScript?
• Can you explain the concept of closures in JavaScript?
• How would you implement a function that removes duplicates from an array in JavaScript?
• Explain the difference between synchronous and asynchronous JavaScript.
• Can you explain the concept of Big O notation and how it relates to algorithmic complexity?
• How would you implement a function that flattens a nested array in JavaScript?
• Can you explain the purpose of the box-sizing CSS property?
• How would you implement a CSS grid layout?
• Describe the difference between the float and position CSS properties.

The final round at Meta for the Frontend Engineer role consists of multiple onsite rounds, including coding rounds, design/architecture round, and career and coding conversation round. Consider exploring the hiring methods for Software Engineers at Google.

1. Coding Rounds: You will have two 45-minute interviews that focus heavily on coding. The engineers will be looking for accurate, bug-free, efficient, and well-thought-out code via whiteboard coding questions. The questions will involve data structures and algorithms, with a practical focus on what you might encounter building user interfaces at Meta. You should provide a narrative as you go through the code to demonstrate your thought process.
   
2. Frontend Design/Architecture Round: The design interview is 45 minutes and doesn’t include coding. Instead, you’ll spend the interview talking and using the whiteboard as a visual aid. The interviewer will ask you a very broad design problem and evaluate your solution. The purpose of the interview is to assess your ability to solve a non-trivial engineering design problem. The interviewer will be trying to determine if you can architect a solution to a higher-level problem that requires connecting multiple concepts. Typically, the interviewer is looking to see that you have a good understanding of some of the concepts like browsers, the DOM, performance, API design, etc. Keep in mind - this is not like a typical System Design interview; think of this as “Frontend System Design” which weighs much more heavily on frontend components.
   
3. Career and Coding Conversation: You’ll meet with Meta’s engineers to talk about two subjects: you and coding. They’ll ask about you, your history, your résumé, and your motivation. The “you” part is behavioral in the sense that it helps the team assess whether you’ll thrive in Meta’s peer-to-peer, minimal-process, collaborative engineering organization. The coding part is a shorter version of the coding interviews earlier in the day. They include a coding question in this interview to supplement and get additional coding signals. Typically, this part of the interview will be HTML and CSS focused.

• Implement a function to reverse a linked list.
• Given an array of integers, write a function to find the two numbers that add up to a specific target value.
• Given two strings, write a function to determine if they are anagrams of each other.
• Implement a function to find the kth smallest element in a binary search tree.
• Implement a function to check if a binary tree is balanced.
• How would you design a social media platform feed?
• Design an online shopping cart system.
• Can you walk me through your experience working with CSS?
• Can you tell me about a time when you had to debug a particularly challenging issue on the Frontend?
• How would you architect the Frontend for a messaging system?