module.exports vs exports in Node.js

In Node.js, both module.exports and exports are used to define the exports of a module, but there are differences in how they can be used.

module.exports

module.exports is the actual object that is returned when you require a module in another file.

When you assign a value directly to module.exports, you replace the entire exports object with your new value.

You can assign any type of value to module.exports, including functions, objects, or primitive values.

// file: myModule.js

// Assigning a function to module.exports
module.exports = function() {
  console.log('Hello from myModule!');
};

exports

exports is a shorthand reference to module.exports.

You can use exports to add properties or methods to the exports object, but you cannot directly assign a new value to exports.

If you try to assign a new value directly to exports, it will break the reference between exports and module.exports.

// file: myModule.js

// Adding a property to exports
exports.myFunction = function() {
  console.log('Hello from myModule!');
};

However, you should avoid directly reassigning exports if you want to maintain the reference to module.exports. If you reassign exports, it will no longer point to module.exports, and your module might not work as expected.

When to use which:

If you are exporting a single object, function, or value, you can use either module.exports or exports.

If you are extending exports with additional properties or methods, use exports.

If you need to replace the entire exports object, use module.exports.

// Preferable usage when extending exports
exports.myFunction = function() {
  console.log('Hello from myModule!');
};

exports.anotherFunction = function() {
  console.log('Another function!');
};

// If you need to replace the entire exports object
module.exports = {
  myFunction: function() {
    console.log('Hello from myModule!');
  },
  anotherFunction: function() {
    console.log('Another function!');
  }
};

In most cases, developers use module.exports when they want to replace the entire exports object and use exports for extending the exports with additional properties or methods. It's essential to be consistent in your usage to avoid potential confusion.

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