销毁导出默认值和module.exports之间的区别

Question

I've been struggling to destruct my mongo object in another file, my object structure is like below.

  const env = {
       project: 'CRIBBBLE BACKEND',
       url: 'localhost',
       api: {
         url: 'https://api.dribbble.com/v1/',
       },
       port: parseInt(process.env.PORT, 10) || 3000,
       mongo: database,
};

 export default env;

But when I'm trying to import the mongo object in another js file like this { mongo } from 'config' the returned value is undefined . But if I change the export default value to module.exports it works as its expected.

So, I'm just wondering what is the difference between module.exports and export default ?

Answer 1

module.exports is a NodeJS ( CommonJS ) style of importing and exporting from different files. import/export is ES6 feature of doing the same thing.

If you export defualt you need to import it like import env from 'location' (Look I emit the {} part) and then access the mongo via env.mongo . You can't just get the mongo object directly.

Answer 2

While you export using export default foo the whole exported foo is available using {default: foo} after import. That's why you cannot access properties you want. Try to import as: import * as bar from './foo' and explore the bar using console.log(bar) to see what's happening underneath. Also for more info have a look: es6 module exports on 2ality.com