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What this article shares to you is about what the Node.js interview questions are easy to be ignored. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

If you want to find a job in Node.js, but don't know where to start to check your mastery of Node.js. This article provides a list of Node.js interview questions to help you assess your mastery of Node.js development by examining some of the main details of Node.js programming.

Before entering the text, you need to declare two points in advance:

These problems are only a part of the Node.js knowledge system, and can not fully examine the actual development ability of the interviewees.

For problems encountered in real-world development, you need to improvise and work as a team, so you can try pair programming.

List of Node.js interview questions

What is an error-first callback function?

How do you avoid calling back to hell?

How do you use Node to monitor port 80?

What is an event loop?

What tools can be used to ensure a consistent style?

What is the difference between operational errors and programmer errors?

Why is npm useful?

What is stub? Can you give me a usage scenario?

What is the Test Pyramid? When we talk about HTTP API, how do we implement it?

What is your favorite HTTP framework and explain why?

Now, let's answer these questions in turn.

What is an error-first callback function?

The error-first callback function is used to pass errors and data. The first parameter should always be an error object to check whether an error has occurred in the program. The rest of the parameters are used to pass data. For example:

Fs.readFile (filePath, function (err, data) {if (err) {/ / handle the error} / / use the data object})

Analysis: the main function of this topic is to check the interviewee's mastery of some basic knowledge of asynchronous operation in Node.

How to avoid callback to hell

You can do this in the following ways:

Modularization: dividing the callback function into separate functions

Use Promises

Use yield to calculate the generator or Promise

Analysis: there are many answers to this question, depending on the scenario you are using, such as ES6, ES7, or some control flow libraries.

How do you monitor port 80 in Node

There's a trap in this question! You should not try to listen on port 80 in Unix-like systems, because this requires superuser privileges, so it is not recommended that your application listen on this port.

Currently, if you want your application to listen on port 80, you can do this: have your Node application listen on ports greater than 1024, and then use a layer of directional proxies (such as nginx) in front of it.

Explanation: this question is used to check whether the interviewee has actual experience in running Node applications.

What is an event loop?

Node only runs on a single thread, at least from the point of view of Node.js developers. At the bottom, Node implements multithreading through libuv.

The Libuv library is responsible for the execution of Node API. It assigns different tasks to different threads to form an event loop and returns the execution result of the task to the V8 engine asynchronously. It can be simply represented by the following picture.

Each IWeiO needs a callback function-- once executed, it is pushed to the event loop for execution.

Explanation: this is used to check the underlying knowledge of Node.js, such as what libuv is and what it does.

The above is easy to be ignored what the Node.js interview questions are, and the editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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