How to assign a JSON object returned inside a promise object into a global variable?

Question

var mongoose = require('mongoose');
var Schema = mongoose.Schema;


const NewsAPI = require('newsapi');
const { response } = require('express');
const newsapi = new NewsAPI();

var current_date = new Date(Date.now());
var old_date = new Date(Date.now() - 864e5 - 864e5);

var current_date2 = JSON.stringify(current_date);
var old_date2 = JSON.stringify(old_date);

var today = current_date2.slice(1,11);
var day_b4_yesterday = old_date2.slice(1,11);

var feed;
newsapi.v2.everything({
    q: 'food and beverage',
    sources: '',
    domains: '',
    from: day_b4_yesterday,
    to: today,
    language: 'en',
    sortBy: 'relevancy',
    page: 2
}).then(response => {
    console.log(response);
    feed = response;

    

});


var NewsSchema = new Schema(feed);
module.exports = mongoose.model('News', NewsSchema);

I need to assign the response which is a JSON object created by the newsapi to a global variable to use it in the new Schema. How do I do that? As of now I'm not able to access it globally.

I have changed my code as follows and now it I'm able to access it but now I'm getting a Schema configuration error.

var mongoose = require('mongoose');
var Schema = mongoose.Schema;


const NewsAPI = require('newsapi');
const { response } = require('express');
const newsapi = new NewsAPI('87ca7d4d4f92458a8d8e1a5dcee3f590');

var current_date = new Date(Date.now());
var old_date = new Date(Date.now() - 864e5 - 864e5);

var current_date2 = JSON.stringify(current_date);
var old_date2 = JSON.stringify(old_date);

var today = current_date2.slice(1,11);
var day_b4_yesterday = old_date2.slice(1,11);


NewsLibrary = function(correct){
    var promise = new Promise(function(resolve, reject){
        if (correct){
            newsapi.v2.everything({
                q: 'food and beverage',
                sources: '',
                domains: '',
                from: day_b4_yesterday,
                to: today,
                language: 'en',
                sortBy: 'relevancy',
                page: 2
            }).then(response => {
                resolve(response);
            })
        }else{
            reject(new Error("Error loading news"))
        }
        

    });

    return promise;
}

NewsLibrary(true).then(function(response){
    console.log(response);
    var NewsSchema = new Schema(response);
    module.exports = mongoose.model('News', NewsSchema);
}).catch(function(err){
    console.log(err)
});

Does this answer your question? [How do I return the response from an asynchronous call?](https://stackoverflow.com/questions/14220321/how-do-i-return-the-response-from-an-asynchronous-call) — Kunal Mukherjee, Jul 25 '20 at 15:33

score 1 · Answer 1 · answered Jul 25 '20 at 17:38

1

You have taken a global variable feed. But you are storing the response in window.feed. So you should store it in feed variable in the then block, That is the first thing.

answered Jul 25 '20 at 17:38

Umar Awan

86
8

score 0 · Answer 2 · answered Jul 25 '20 at 14:24

0

You can assign it by using global or GLOBAL, nodejs supports both:

global.feed = response;

or

GLOBAL.feed = response;

answered Jul 25 '20 at 14:24

White Link

106
7

When I try to console the value of feed outside the then function it reurns me undefined. – Kritartha Borthakur Jul 25 '20 at 14:34
You mean the feed itself or the global.feed value? – White Link Jul 26 '20 at 04:17

boredfromboredom · Answer 3 · 2020-07-25T16:33:25.447

0

I think the main problem is because the method is asynchronous.

var NewsSchema = new Schema(feed);

This code should only work after the request is complete. But I think it would run before the request is complete because it is given outside the promise (the then statement).

Ideally you should return a promise from this method or a function which will return the correct value and handle the promise in the module which imports this. An example would be,


var model = newsapi.v2.everything({
    q: 'food and beverage',
    sources: '',
    domains: '',
    from: day_b4_yesterday,
    to: today,
    language: 'en',
    sortBy: 'relevancy',
    page: 2
}).then(response => {
    console.log(response);
    var NewsSchema = new Schema(response);
    return mongoose.model('News', NewsSchema);
});


module.exports = { model };

You can handle the resolution of this promise in the file or method which requires this. If interested in more asynchronous code look here at MDN web docs,

edited Jul 25 '20 at 16:33

answered Jul 25 '20 at 15:31

boredfromboredom

173
1
4

I tried this example but it throws an error stating Schema hasn't been registered for model "News". – Kritartha Borthakur Jul 25 '20 at 16:21
I had made an error in the previous code has corrected it please try again. Remember that requiring this file will return a promise – boredfromboredom Jul 25 '20 at 16:34
I actually tried something similar to what you suggested what it's the same error. – Kritartha Borthakur Jul 25 '20 at 17:29
`var NewsSchema = newsapi.v2.everything({ q: 'food and beverage', sources: '', domains: '', from: day_b4_yesterday, to: today, language: 'en', sortBy: 'relevancy', page: 2 }).then(response => { console.log(response); return mongoose.model('News', new Schema(response)); }); module.exports = {NewsSchema} ;` – Kritartha Borthakur Jul 25 '20 at 17:31
I have not worked that much with mongoose. But doesn't it need to define the Schema before hand. If you need to inert without knowing about the schema try https://stackoverflow.com/questions/5370846/how-do-you-use-mongoose-without-defining-a-schema. But in most cases you need to know about the schema if the data. – boredfromboredom Jul 26 '20 at 02:44

How to assign a JSON object returned inside a promise object into a global variable?

3 Answers3