How to export the contents of a promisse that is in a module to another module?

Question

I have the following module getToken.js:

var rp = require('request-promise');

const options = {
    url: 'https://meuservidor:8080/nifi-api/access/token',
    method: 'POST',
    gzip: true,
    rejectUnauthorized: false,
    headers: {
        'Accept-Encoding': 'gzip, deflate, br',
        'Content-Type': 'application/x-www-form-urlencoded; charset=UTF-8'
    },
    body: 'username=meuusuario&password=minhasenha'
}

rp(options)
    .then(function(body) {
        console.log(body)
    })
    .catch(function(err) {
        console.log(err)
    })

How to export content from console.log(body) to another module?

Answer 1

In short, you cannot export the resolution (or rejection) value of the promise. To learn more about why, read this answer. Thus, an option is to export the Promise, and use the then and/or catch in the module that imports it.

So, in the module you export, you must export to Promise. Therefore:

// ...

// `rp` é uma função que retorna uma `Promise`.
module.exports = rp();

And to import:

const bodyPromise = require('./my-module.js');

bodyPromise.then((body) => /* Do stuff. */); // Não se esqueça do `catch`. :-)

Another option would be to export the function rp, using module.exports = rp. However, this would make you have to call this function in the modules that import it. By always exporting the Promise (the value returned by the function), you assume the argument passed options will always be the same. If this is not what you need, you should export the function, not your return-the promise.