What are the differences between : "module.exports = { foo, bar };" and "module.exports = foo, bar;"?

[marc.scherzer]

Hi, I have controller code in back-end :

const getText = (req, res) => {
  res.status(200).json({
    message: "Get text",
  });
};

const setText = (req, res) => {
  res.status(201).json({
    message: "Set text",
  });
};

at the bottom of the file, I want to export them but I am confused either :

module.exports = { getText, setText };

or

module.exports = getText, setText;

Which one is correct or more proper ?
Thank you.

[jenovs]

First one. The second one won’t even work.

[lasjorg]

Well, it won’t work as expected. But it will sort of work, it will just only export the first variable. So you would only have access to getText.

It is just a property with an object.

const module = {
  exports: {},
};

module.exports = 'valueOne', 'valueTwo';
console.log(module.exports); // 'valueOne'

If you need multiple values you can either assign them to properties

module.exports.getText = getText;
module.exports.setText = setText;

Or you can wrap the values in a data structure that can contain multiple values like an object as your second example.

module.exports = { getText, setText };

You can also try logging out module inside your code to see it.

console.log(module)
module.exports = getText, setText;
console.log(module)

[DanCouper]

Just to expand, module.exports is for you to define the default export of a module (equivalent to export default when using native JS modules).

So module.exports = { getText, setText }; is saying “make the default export of this module an object which has two properties (getText and (setText)”

Second version uses this:

Comma operator (,) - JavaScript | MDN

So module.exports = getText, setText is saying “make the default export of this module the function getText, then evaluate the function setText (which will do nothing)”

[marc.scherzer]

Thank you very much, I got it !