问题
I have started working on an existing project based on nodejs. I was just trying to understand the flow of execution, where I encountered with some .mjs files. I have searched the web where I found that these are module based JS files.
I want to know how is it different from .js files (how does it benefit) ?
回答1:
Node.js's native module system is CommonJs.
It has experimental support for the standard ES6 module system and using a .mjs file extension is part of one way to trigger that support.
In short, it is used by Node.js to distinguish between CommonJS and ES6 module files.
Differences between ES6 module system and CommonJs
回答2:
.MJS file
- mjs an extension for EcmaScript modules
- An MJS file is a source code file containing an ES Module (ECMAScript Module) for use with a Node.js application.
MJS files are written in JavaScript, and may also use the .JS extension outside of the Node.js context.
ES Modules allow web and application developers to organize code into smaller reusable components.
ECMAScript 6 (ES6) introduced the specification for ES Modules, providing a standard for implementing modules in JavaScript. As of 2018, all major web browsers support ES Modules.
However, the popularity of modularized JavaScript pre-dates ES6. Node.js, a JavaScript runtime environment, used CommonJS as the specification for modules. Because so many existing applications were built with CommonJS, when Node.js added support for native ES modules, it controversially introduced the MJS file extension to differentiate the two and prevent applications from breaking.
NOTE: Some developers informally refer to MJS files as "Michael Jackson Script" files.
来源：https://stackoverflow.com/questions/57492546/what-is-the-difference-between-js-and-mjs-files