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This article mainly introduces what node.js common interview questions are, which can be used for reference by interested friends. I hope you will gain a lot after reading this article. Let's take a look at it.

1. Give an example of your favorite HTTP framework and its reasons

There is no only answer to this question. This question mainly examines the interviewee's understanding of the Node framework he uses, and whether he can give reasons for choosing the framework, advantages and disadvantages, and so on. You can refer to this website for the commonly used HTTP framework.

2. What is the 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.

3. 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.

4. Which tools can be used to ensure a consistent code style

You can choose the following tools:

JSLint

JSHint

ESLint

JSCS-recommended

In team development, these tools are very helpful for writing code, help team developers enforce prescribed style guidelines, and catch common errors through static analysis.

Analysis: used to check whether the interviewee has experience in developing large-scale projects.

5. What are the benefits of using NPM?

With NPM, you can install and manage project dependencies and specify the specific version number of the dependency. For Node application development, you can use package.json files to manage project information, configure scripts, and specify the specific version on which the project depends.

Parsing: it examines the interviewer's basic knowledge of using the npm command and the practical experience of Node.js development.

6. What is Stub? Give an example of a usage scenario.

Stub is a function or program used to simulate a component or module. In test cases, simply put, you can use Stub to simulate a method to avoid calling real methods, and with Stub you can return fictional results. You can use Stub with assertions.

For example, in a scenario where you read a file, when you don't want to read a real file:

Var fs = require ('fs')

Var readFileStub = sinon.stub (fs, 'readFile', function (path, cb) {

Return cb (null, 'filecontent')

})

Expect (readFileStub). To.be.called

ReadFileStub.restore ()

In unit testing: Stub completely simulates an external dependency, while Mock is often used to determine whether a test passes or fails.

Analysis: used to test whether the interviewee has testing experience. If the interviewee knows what Stub is, you can continue to ask him how to do the unit test.

7. What is the test pyramid?

The test pyramid means that when we write test cases, there should be far more unit tests at the bottom than end-to-end tests at the top.

When we talk about HTTP API, we may refer to:

There are a lot of underlying unit tests for the model

But when you need to test how models interact, you need to reduce integration testing

Analysis: this paper mainly examines the interviewees' experience in testing.

Thank you for reading this article carefully. I hope the article "what are the test questions you often meet with node.js" shared by the editor will be helpful to you. At the same time, I also hope that you will support us and pay attention to the industry information channel. More related knowledge is waiting for you to learn!

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