Nodejs does not use es6 module

Node.js is a JavaScript runtime based on the Chrome V8 engine that allows developers to write server-side applications using JavaScript. It uses an event-driven non-blocking I/O model, allowing Node.js to handle a large number of concurrent requests. In addition, Node.js can also use the module system to achieve code reuse and separation functions.

ES6 is the abbreviation of ECMAScript 2015. It is an update and extension to JavaScript, adding a large number of new features, such as arrow functions, let/const, destructuring assignment, template strings, classes, etc. At the same time, ES6 also introduces the concept of modularity to JavaScript, implementing code modular management through import and export statements, improving the readability and maintainability of the code.

Using ES6 modules has become very common in front-end development, but in Node.js, using ES6 modules is not necessary. Node.js introduced stable ES Modules (ESM) support in version v12.16.0, allowing developers to use import and export statements to implement code modularization. But in previous versions, Node.js provided another modular system - CommonJS modules, using require and module.exports syntax.

Compared with ES6 modules, CommonJS modules have the following advantages:

1. Compatibility
CommonJS modules are supported in all versions of Node.js and do not need to be used like ES6 Modules also require additional processing in terms of syntax and configuration.

2. Ease of use
In Node.js, using the CommonJS module only requires the require and module.exports syntax to achieve modular management, and does not require additional configuration and syntax usage constraints.

3. Community support
In the Node.js community, a large number of packages use CommonJS modules for code organization and distribution. These packages are widely supported in a large number of npm package managers and scaffolding. and use. Using CommonJS modules can avoid compatibility issues caused by different syntaxes.

4. Dependency management
In Node.js, dependency management using the CommonJS module is very convenient, because the code and dependencies contained in a module can share the same scope, reducing the complexity of the code. Coupling and complexity.

In the process of using the CommonJS module, we need to pay attention to the following points:

1. Caching mechanism
Node.js will cache the module objects that have been used and try again next time No need to reload when using. This means that if a module's code is modified, the cache will need to be cleared before the changes can be seen.

2. Circular dependencies
CommonJS modules can load and use other modules through the require statement, but if two modules reference each other, a circular reference problem will occur. At this time, you need to place a reference to one of the modules within the function instead of directly referencing it at the top of the module.

In general, you need to pay attention to the above points when using CommonJS modules in Node.js, but in most cases, using CommonJS modules can achieve simple and efficient code organization and modular management, thereby improving Code readability and maintainability.

Of course, in the new version of Node.js, the use of ES6 modules has been better supported, and will become more and more common in future development. Therefore, it is also necessary to understand and use ES6 module syntax. Ultimately, we can choose the appropriate modular system to use based on the actual project conditions.

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