bluebird Converting a callback API to promises. Converting a single NodeJS function
Example
You can convert a single function with a callback argument to a Promise-returning version with Promise.promisify, so this:
const fs = require("fs");
fs.readFile("foo.txt", (err, data) => {
if(err) throw err;
console.log(data);
});
becomes:
const promisify = require("bluebird");
const readFile = promisify(require("fs").readFile));
readFile("foo.txt").then(console.log); // promisified version
