Question-31. How do you create a simple server in Node.js that returns Hello World?

simple-server

  • Import the HTTP module
  • Use createServer function with a callback function using request and response as parameters.
  • Type “hello world.”
  • Set the server to listen to port 8080 and assign an IP address

Question-32. Explain asynchronous and non-blocking APIs in Node.js.

  • All Node.js library APIs are asynchronous, which means they are also non-blocking
  • A Node.js-based server never waits for an API to return data. Instead, it moves to the next API after calling it, and a notification mechanism from a Node.js event responds to the server for the previous API call

Question-33. How do we implement async in Node.js?

Answer- As shown below, the async code asks the JavaScript engine running the code to wait for the request.get() function to complete before moving on to the next line for execution.

async

Question-34. What is a callback function in Node.js?

Answer- A callback is a function called after a given task. This prevents any blocking and enables other code to run in the meantime.

In the last section, we will now cover some of the advanced-level Node.js interview questions.

Question-35. What is REPL in Node.js?

Answer- REPL stands for Read Eval Print Loop, and it represents a computer environment. It’s similar to a Windows console or Unix/Linux shell in which a command is entered. Then, the system responds with an output

repl2

Question-36. What is the control flow function?

Answer- The control flow function is a piece of code that runs in between several asynchronous function calls.

Question-37. How does control flow manage the function calls?

function-calls

Question-38. What is the difference between fork() and spawn() methods in Node.js?

fork() spawn()
spawn
fork() is a particular case of spawn() that generates a new instance of a V8 engine. Spawn() launches a new process with the available set of commands.
Multiple workers run on a single node code base for multiple tasks. This method doesn’t generate a new V8 instance, and only a single copy of the node module is active on the processor.

Question-39. What is the buffer class in Node.js?

Answer- Buffer class stores raw data similar to an array of integers but corresponds to a raw memory allocation outside the V8 heap. Buffer class is used because pure JavaScript is not compatible with binary data.

Question-40. What is piping in Node.js?

Answer- Piping is a mechanism used to connect the output of one stream to another stream. It is normally used to retrieve data from one stream and pass output to another stream

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