How to write code for node js?

Question

JavaScript

let obj;
fs.readFile("config.json", (err, data) => {
    if (err){
        console.log(err);
    } else {
        obj = JSON.Parse(data);
    }
});
console.log(obj);

The problem is that obj will be undefined, but I need to somehow work with this variable further, and I don’t want to write huge logic in the else branch of the callback, how is this problem solved? Sync cannot be used.

Answer 1

new Promise((resolve, reject) => {
  fs.readFile("config.json", (err, data) => {
    if(err) {
      return reject(err);
    }
    resolve(JSON.Parse(data));
  });
}).then(obj => {
  console.log(obj);
  // your code
}).catch(console.error);

Answer 2

Specifically, here it is easier to use synchronous reading of the file, and given that this is generally json, let obj = require('./config.json');