The nodejs directory does not exist and is automatically created.

With the rapid development of the Internet and the increase in the amount of information, Node.js has been widely used in website development, API construction, data applications and other fields. In Node.js development, the creation and management of directories is also a very important issue. Normally, when performing file/folder operations, if the directory we need to operate does not exist, the system will throw an exception, making our program unable to proceed normally. Therefore, in order to optimize our program, we need to define specific methods in the code for automatic directory creation.

This article will introduce the commonly used automatic directory creation methods in Node.js, as well as their respective advantages, disadvantages and usage scenarios.

1. fs.mkdir

fs.mkdir() is the API that comes with Node.js. It is used to create directories. Its definition is as follows:

fs.mkdir(path[, options], callback)

Among them, The parameter path represents the path of the directory to be created; the parameter options is optional and represents the attributes of the directory, and the default value is 0o777 (that is, all users have read, write, and execute permissions); the parameter callback is a callback function that is used when the directory is created successfully or Execute after failure.

Simply put, the fs.mkdir method determines whether the directory needs to be created by checking whether the directory at the specified path exists. If the directory does not exist, it attempts to create it.

The following is an example of using fs.mkdir to create a directory:

const fs = require('fs');

fs.mkdir('/path/to/dir', { recursive: true }, (error) => {
    if (error) {
        console.error(`创建目录失败：${error}`);
    } else {
        console.log('目录创建成功');
    }
});

In this example, the parameter recursive is set to true to achieve automatic creation of the directory. If this parameter is not set to true, an exception will be thrown if any of the directory's parent directories does not exist.

2. mkdirp

mkdirp is a third-party module of Node.js, which provides a more convenient way to create directories. Different from fs.mkdir, mkdirp will automatically determine whether the directory exists. If it does not exist, it will create the directory; if the directory exists, it will automatically return.

The usage is as follows:

mkdirp(dir, [options], function (err) {
    if (err) console.error(err);
    else console.log('成功创建目录：' + dir)
});

Among them, the parameter dir represents the directory path to be created, and the parameter options is optional and represents the attributes of the directory; the callback function can be used after the directory creation is successful or failed. implement.

The difference between mkdirp and fs.mkdir is that it can create directories recursively and supports success/failure processing through callback.

3. New methods in Node.js 10

In Node.js 10, the fs.mkdir method adds a recursive parameter for recursively creating directories. If this parameter is set to true, the superior directory can be automatically created when the directory is created.

The usage method is as follows:

const fs = require('fs');

fs.mkdir('/path/to/dir', { recursive: true }, (error) => {
    if (error) {
        console.error(`创建目录失败：${error}`);
    } else {
        console.log('目录创建成功');
    }
});

Before Node.js 10, when creating a directory directly as in the above code, you must manually create the parent directories of the directory at all levels first. After Node.js 10, automatic creation can be achieved after setting recursive to true.

4. Summary

The above is the commonly used Node.js directory automatic creation method. In actual development, we can choose the appropriate method according to actual needs. The new fs.mkdir method in Node.js 10 is more concise and efficient than the previous writing method, but it is only applicable to Node.js 10 and above. If you need compatibility with older Node.js versions, you can use the mkdirp module. At the same time, fs.mkdir is also a good choice. There is no need to introduce third-party modules and you can directly use the API that comes with Node.js.

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