Variables in JS Node

Question

wanted to understand more the concept of variables in NODE.
I tried to make a simple code to read a json from the internet.
I created a variable to receive the name of the title, but after set, it returns to the old value.
I’m starting now and wanted to understand more about how variables work on Node.

Thank you!

const express = require('express');
const request = require('request');

const app = express();

app.get('/', (req, res) => {
    let encryptTitle = 0
    request.get({
        url: 'https://my-json-server.typicode.com/typicode/demo/posts',
        json: true
    },
         (error, response, body) => {
            encryptTitle = body[1].title
            console.log(encryptTitle) // retorna Post 2
    });

    console.log(encryptTitle) // retorna 0
    res.send("Hello Worlds")
})


app.listen(3000);

Answer 1

The variable is correct, the problem is that in Javascript IO (network, file, etc) tasks are performed asynchronously. The problem here is that the log that returns "0" is executed during the request. The log that returns "Post 2" is executed only when your request is completed, well after the log that returns 0 is executed.

The problem is related to the asynchronous part of Javascript and essential to master the language. I recommend reading the various ways to write this code, in general callbacks, Promises and async are used.

Good studies!