面試官筆記 - 1 - Mark Ku's Tech Notes

Front-end-interview

Please introduce yourself from a technical perspective — walk me through what you've worked on over the past few years. Keep it within five minutes.

Interviewer self-introduction: role overview, responsibilities, and what we're looking for in this position
Ask the candidate to highlight relevant experience based on what was just described
What was your role at your last job? Can you walk me through a project you're most proud of?
What are your expectations? What's the one thing you most want to learn this year?
Have you been following any new technologies lately? Any takeaways? Have you tried them out? Any open-source work to share?
Do you enjoy writing code? What aspect of coding do you find most interesting?
Whiteboard: write a string reversal function
What did you learn from your previous job?
Have you been reading any programming-related books recently?

After a user logs in on one page, how does the next page know they're authenticated?
Where do you typically store frequently used user data?

Have you implemented caching before? When should caching be used?
How do you optimize a website's static assets? How do you bundle them — into how many files, and how do you decide? How do you debug after bundling?
If a static file is cached and a new version is released, how do you force an update? Version numbers in filenames? Any other approaches?
Have you used a CDN before?
Walk me through a few techniques you've used to speed up page load times.
An article-listing website needs to frequently query 50+ posts for the homepage — how would you handle that?
Have you ever dealt with complaints about slow page loading? What was the situation and how did you resolve it? Where do you look first?
You have around 500 records to display paginated on a web page — how would you approach it? What about 50,000 records?
When do you populate an in-memory cache? If it sacrifices startup time and slows down development, how do you handle that?
When there are multiple application servers, how do you handle caching? If the cache lives in a database, who is responsible for updating it?
Have you ever encountered slow database queries in production? How would you investigate? How do you determine whether the bottleneck is network, query, or something else?

How does fetching data via Ajax affect SEO?
What are the key factors in SEO? What optimizations have you implemented? What tools have you used?
Meta tags, keywords, title, responsive design, content quality, server-side rendering, routing, URL rewrite, canonical URL, user experience, robots.txt
When a site is under maintenance, crawlers may still visit — how do you handle that?

What languages/frameworks have you written tests in?
If the function you're testing calls updateDB, how do you handle that in your test?
What is TDD? Does it make a practical difference compared to writing tests after the code?
Have you used any design patterns specifically to support TDD?
What about BDD?
What end-to-end testing tools have you used?

If you needed to log the input and output of every request, how would you implement that?
When would you use an interface?

If a user's order data disappeared on the frontend, where would you start looking?
How would you query logs across 10 servers?

Three clients — a website, a mobile browser, and a mobile app — all consume the same API. The mobile app gets a new version that requires a different data format for one field. How do you handle this without breaking the others?
Have you built a real-time application? If a backend service needs to push a message to a specific user, Andy, how would you route it? How do you know which connection ID maps to Andy? If the mapping is stored per-server and there are multiple servers, how do you resolve the mapping?

What is the difference between placing <script> in the <head> vs. at the end of <body>? What about <link rel="stylesheet">?
What is the difference between <script async> and <script defer>?
Implement: duplicate([1,2,3,4,5]) → result: [1,2,3,4,5,1,2,3,4,5]
== vs. ===
How do you make a cross-origin AJAX request from client A to domain B?
Explain closures
Front-end frameworks: React — state vs. props; Angular — directives
Node.js / Express: how does Express handle errors, requests, responses, and next?
Deferred / Promise: what are resolve and reject? Where have you used Promises?
Explain JavaScript hoisting
Primitive types vs. reference types
List the differences between regular functions and arrow functions
Walk me through what happens when you type "google.com" into the browser address bar and press Enter
Why is setInterval not precise with timing?
What is the difference between var and let?

What is your understanding of single-page applications (SPA)? What are their advantages and disadvantages?
What is the difference between v-show and v-if?
How do you dynamically bind class and style?
What is the difference between computed and watch? When would you use each?
How do you understand the Vue component lifecycle?
What are the different ways components can communicate in Vue?
How do you implement inheritance in Vue?
What is the difference between Vue.extend and mixins?
If a Vue observed object is mutated but the view doesn't update, what would you do?