What does module.exports mean?

In Node.js, module.exportsa special object used to export functions, objects, or values ​​in a module so that other files can require()use them through functions. This is part of the CommonJS module system and Node.js supports it natively.

Example

Suppose you have a math.jsfile called which contains an addition function and a subtraction function:

// math.js
function add(a, b) {
    
    
  return a + b;
}

function subtract(a, b) {
    
    
  return a - b;
}

module.exports = {
    
    
  add,
  subtract
};

By using module.exports, you can export addthe and subtractfunctions for use in other Node.js files.

Now, in another file, you can import and use these two functions like this:

// app.js
const math = require('./math');

console.log(math.add(5, 3));  // 输出 8
console.log(math.subtract(5, 3));  // 输出 2

Notice

• module.exportsAny JavaScript type (function, object, array, string, etc.) can be exported.
• If you use ES6 syntax, module.exportsand requirecan be replaced with exportand respectively import, but be aware that they have some differences in syntax and functionality.
• In a module, you can use it multiple times module.exports, but only the last assignment will take effect.

This way, you can organize your code to make it easier to manage and test.