Server-Side JavaScript and Node.js Interview Questions
Server-side JavaScript comes up in backend interviews. Here are the common questions and how to answer them.
Server-Side JavaScript and Node.js Interview Questions
Server-side JavaScript and Node.js come up in backend interviews. Here are the common questions.
How does JavaScript run on the server?
JavaScript runs on the server through Node.js, which uses the V8 engine to compile and execute JS. Unlike the browser, server JS has access to the file system, network, and processes through libuv.
What is the event loop in Node.js?
A single-threaded loop that processes callbacks from completed async operations. It makes Node.js non-blocking by handling I/O asynchronously through libuv while processing one callback at a time.
What is the difference between blocking and non-blocking code?
Blocking code stops the thread until it completes. Non-blocking code initiates the operation and processes the result via a callback when done. In Node.js, always prefer non-blocking async APIs to keep the event loop free.
What is libuv?
A C library that provides async I/O for Node.js. It handles the event loop, file system operations, network operations, and the thread pool for blocking work. Without libuv, Node.js would not be non-blocking.
What are the main differences between browser and server JavaScript?
Browser JS has the DOM, window, fetch, and a sandbox. Server JS has fs, http, process, full system access, and no DOM. They share the language but differ in environment, APIs, and security model.
The Takeaway
Know how JS runs on the server (V8 and libuv), the event loop, blocking vs non-blocking, what libuv is, and browser vs server differences. These are the core server-side JavaScript interview questions.
Through Node.js, which uses the V8 engine to compile and execute JS. Unlike the browser, server JS has access to the file system, network, and processes through libuv, which provides async I/O.
A single-threaded loop that processes callbacks from completed async operations. It handles I/O asynchronously through libuv while processing one callback at a time, which makes Node.js non-blocking.
Blocking code stops the thread until it completes. Non-blocking code initiates the operation and processes the result via a callback when done. Always prefer non-blocking async APIs in Node.js to keep the event loop free.
A C library that provides async I/O for Node.js. It handles the event loop, file system operations, network operations, and the thread pool for blocking work. Without libuv, Node.js would not be non-blocking.
Browser JS has the DOM, window, fetch, and a sandbox. Server JS has fs, http, process, full system access, and no DOM. They share the language but differ in environment, APIs, and security model.
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