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processing json with fetch returns undefined for valid json key

I need to request data from my REST server to populate my UI (frontend). In doing so, I need to request some data from my and other servers. One such request is to get a list of states (provinces), process each one and add them to a select HTML component. I use fetch() and .json() amongst other tools to do this.
Problem:
In calling my REST server for json data, I receive the following data (taken from Chrome console):
{provinces:[Eastern Cape,Mpumalanga,Western Cape,Gauteng,KwaZulu Natal,North West,Northern Cape,Free
State,Limpopo]}
I intend to add each of these as an option to a select. While attempting to acquire the value for the provinces key, I get undefined.
I am making this call using:
fetch("http://localhost:3443/app/location/provinces").then(e => e.json()).then(e => console.log(e.provinces));
Further, since I can directly refer to json keys using the [] operator, I attempt this using
fetch("http://localhost:3443/app/location/provinces").then(e => e.json()).then(e => console.log(e['provinces']));
which as you may have guessed aswel, also returns undefined.
For the record, the full Chrome Console output is
Promise {<pending>}
undefined
Looking over some SO examples, I believe my call(s) may be correct, this one, and this one, and this one all which confirm its validity.
What else have I tried:
This SO post and this one suggested to use the json data response inside of the same then() call e.g.
fetch("http://localhost:3443/app/location/provinces").then(e => {
e.json().then(s => {
console.log(s['provinces']);
});
});
and
fetch("http://localhost:3443/app/location/provinces").then(e => {
e.json().then(s => {
console.log(s.provinces);
});
});
both which return:
Promise {<pending>}
undefined
What am I missing / doing wrong?
Update
Screenshot of Chrome console in order of commands listed above:
Resource file za-province-city.json
NodeJS express code:
const express = require('express');
const router = express.Router();
const fs = require('fs');
const raw = fs.readFileSync("./res/za-province-city.json");
const map = JSON.parse(raw);
const mapProvinceCity = {};
map.forEach(item => {
if (!mapProvinceCity.hasOwnProperty(item.ProvinceName)) {
mapProvinceCity[item.ProvinceName] = [];
}
mapProvinceCity[item.ProvinceName].push(item.City);
});
for (let key in mapProvinceCity) {
mapProvinceCity[key].sort((a, b) => a.toLocaleString().localeCompare(b.toLowerCase()));
}
router.get('/location/provinces', function (req, res, next) {
let strings = Object.keys(mapProvinceCity);
let json = JSON.stringify({provinces: strings}).replace(/"/g, '');
return res.json(json);
});
router.get('/location/:province/cities', function (req, res, next) {
let province = req.param('province');
let cities = mapProvinceCity[province];
let json = JSON.stringify({cities: cities}).replace(/"/g, '');
return res.json(json);
});
module.exports = router;
Note: if you are wondering about the replace(), each time I requested data in postman, I got

I think your issues all stem from a misunderstanding of Express' res.json().
This is basically a shortcut for
res.set("Content-type: application/json")
res.status(200).send(JSON.stringify(data))
I imagine your problems started when you thought you needed to stringify your data. What happens then is that your data is double-encoded / double stringified, hence the extra quotes. Removing the quotes though mangles your data.
console.log() is not a particularly good debugging tool as it obfuscates a lot of information. In your code, s is actually a string
"{provinces:[Eastern Cape,Mpumalanga,...]}"
I suggest you use the actual debugger instead.
The simple solution is to use res.json() as intended
router.get('/location/provinces', function (req, res, next) {
return res.json({ provinces: Object.keys(mapProvinceCity) });
});
with your client-side code looking like
fetch("http://localhost:3443/app/location/provinces")
.then(res => {
if (!res.ok) {
throw res
}
return res.json()
})
.then(data => {
console.log('Provinces:', data.provinces)
})
This goes for all your Express routes. Do not use JSON.stringify().

How do I reference my MongoDB data in NodeJS, and then add it to a Discord.JS message?

I'm trying to pull an array of data from a MongoDB database, and while the code is rusty (and I do want some corrections on it if it could be done better or is missing something or is wrong), it should be taking the array, finding the "user" and "description" objects, and then putting them into a discord.js message.
I've tried referencing the objects individually, making them strings, parsing the data, but I still cant find out how to do it. Heres the code I've been using.
module.exports.run = async (bot, message, args) => {
const MongoClient = require('mongodb').MongoClient;
const url = 'mongodb+srv://something:something#something/test?retryWrites=true&w=majority';
const assert = require('assert');
try {
function remindersChecker() {
let mongoClientPromise = MongoClient.connect(url, function (err, client) {
const db = client.db("reminders");
let date = new Date().getTime();
let now = Math.floor(Date.now() / 1000);
db.collection("reminders").find().toArray(function (err, result) {
let data = JSON.toObject();
console.log(data);
let user = data.author
let description = data.description
console.log(user);
user.send("I have a reminder for you! " + description)
})
})
}
remindersChecker()
} catch(err) {
catchError()
}
}}
module.exports.help = {
name: "check"
}
(The command is temporary and will be used on a setTimeout later, hence the function rather than just plain old code.)
Thanks! And I hope I can get help soon.

probably some more information would be great to better understand the problem.
from what i can see here, you are receiving an object from your database and converting it into an array here:
db.collection("reminders").find().toArray(function (err, result) {...
now that array is actually that result obtained from the callback and you are not using it at all, you probably have to iterate on that.
plus i remember that I used to write
...find({})..
to search in the database as for SELECT*FROM in SQL. maybe that can help too.
hope this helps.

Node.js how to return an array from within a asynchronous callback for use in another file

File called testing.js
I can do whatever I like with the data in saveWeatherData but cannot call this function and return the data without getting 'undefined'
For example if i tried the below code in saveWeatherData it will print out the summary as expected...
console.log(The summary of the weather today is: ${dataArray[0]});
However I want to use these values within another file such as a server file that when connected to will display weather summary temperature etc.
So I need to return an array with these values in it so that I can call this function and get my data stored in an array for further use.
I know that the reason the array --dataArray is returning undefined is because asynchronous code.
The array is returned before we have gotten the data using the callback.
My question, is there anyway to do what I am trying to do?
I tried my best to explain the problem and what I want to do, hopefully its understandable.
Would I have to use a callback inside of a callback? To callback here to return the data when its been fetched?
I just cant get my head about it and have tried multiple things to try and get the result I am looking for.
My last idea and something i would prefer not to do is the use the 'fs' module to save the data to a text or json file for use in my other files through reading the data from the saved file...
I feel im close but cant get over the last hurdle, so ive decided to ask for a little help, even just point me on the right track and Ill continue to try and figure it out.
Phew...
Thank you for your time!
const request = require("request");
let dataArray = [];
let saveWeatherData = function(weatherData) {
dataArray = weatherData;
return dataArray;
};
let getWeatherData = function(callback) {
request({
url: `https://api.forecast.io/forecast/someexamplekey/1,-1`,
json: true
}, (error, response, body) => {
//Creating array to hold weather data until we can save it using callback...
let array = [];
if (error) {
console.log("Unable to connect with Dark Sky API servers.")
}
else {
console.log(`Successfully connected to Dark Sky API servers!\n`);
array.push(body.currently.summary, body.currently.temperature, body.currently.apparentTemperature, body.currently.windSpeed, body.currently.windBearing);
callback(array);
}
});
};
getWeatherData(saveWeatherData);
module.exports = {
saveWeatherData
};
My Other File...
File called server.js
const http = require("http");
const testing = require("./testing");
function onRequest(request, response){
let data = testing.saveWeatherData();
console.log(`A user made a request: ${request.url}`);
response.writeHead(200, {"context-type": "text/plain"});
response.write("<!DOCTYPE html>");
response.write("<html>");
response.write("<head>");
response.write("<title>Weather</title>");
response.write("</head>");
response.write("<body>");
response.write("Weather summary for today: " + data[0]);
response.write("</body>");
response.write("</html>");
response.end();
}
http.createServer(onRequest).listen(8888);
console.log("Server is now running on port 8888...");

I'm still not sure about what are you trying to do. However, I think you're not exporting what you suppose to be exporting. To avoid the use of so many callbacks you may use async/await.
Change this part of your server.js
async function onRequest(request, response) {
let data = await testing.getWeatherData();
console.log(`A user made a request: ${request.url}`);
response.writeHead(200, { 'context-type': 'text/plain' });
response.write('<!DOCTYPE html>');
response.write('<html>');
response.write('<head>');
response.write('<title>Weather</title>');
response.write('</head>');
response.write('<body>');
response.write('Weather summary for today: ' + data[0]);
response.write('</body>');
response.write('</html>');
response.end();
}
And this of your testing.
let getWeatherData = function() {
return new Promise(resolve =>
request(
{
url: `https://api.darksky.net/forecast/someexamplekey/1,-1`,
json: true
},
(error, response, body) => {
//Creating array to hold weather data until we can save it using callback...
let array = [];
if (error) {
console.log('Unable to connect with Dark Sky API servers.');
} else {
console.log(`Successfully connected to Dark Sky API servers!\n`);
array.push(
body.currently.summary,
body.currently.temperature,
body.currently.apparentTemperature,
body.currently.windSpeed,
body.currently.windBearing
);
resolve(array);
}
}
)
);
};
module.exports = {
getWeatherData
};
It will check for new Weather in each request. If you want to save the result to avoid checking every single time you might need to do something else. But I think for a weather app the important is to keep it updated.

NodeJS Undefined JSON object

just posting a question as I have seen some other similar questions on here but none with a method that seemingly works for me.
I'm new to NodeJS and playing around with requesting data from an API. For my test here im just trying to pull ticker prices based on the input of a prompt from the user.
This works fine, however the object
This is the code I am using to try and make this work:
prompt.start();
prompt.get(['coin'], function (err, result) {
request({url: `https://min-api.cryptocompare.com/data/price?fsym=${result.coin}&tsyms=BTC,USD`, json:true}, function(err, res, json) {
if (err) {
throw err;
}
console.log(json);
var json = JSON.stringify(json);
var string2 = JSON.parse(json);
console.log(string2.btc_price);
console.log(json);
});
console.log('Retrieving: ' + result.coin);
});
The API request works, however it returns JSON that looks like this with my 3 console logs:
{ set_attributes: { btc_price: 1, usd_price: 15839.35 } }
undefined
{"set_attributes":{"btc_price":1,"usd_price":15839.35}} -- (Stringify'd response)
I want to be able to extract the btc_price & usd_price as variables, ive tried a few different methods and can't figure out where exactly im going wrong. Any help would be greatly appreciated!
Cheers,
J

When you attempt to extract the btc_price attribute, it's actually nested so your second console should read console.log(string2.set_attributes.btc_price);

axios has more stars on Github, more followers on Github and more forks.
Features
Make XMLHttpRequests from the browser
Make http requests from node.js
Supports the Promise API
Intercept request and response
Transform request and response data
Cancel requests
Automatic transforms for JSON data
Client side support for protecting against XSRF
Using async / await
// Make a request for a user with a given ID
var preload = null;
async function getPrice(symbol) {
preload = await axios.get('https://min-api.cryptocompare.com/data/price?fsym=${symbol}&tsyms=BTC,USD')
.then(function (response) {
preload = response.data;
})
.catch(function (error) {
console.log(error);
});
return `preload.BTC = ${preload.BTC}; preload.BTC = ${preload.BTC}`;
};
getPrice('ETH');
// return preload.BTC = 0.04689; preload.USD = 742.85

How can I display the output(HTML) depending on its id on node js using sqlite

Here is my code on Node JS. And can you give an example what will i add in the HTML code. Thank you
exports.get = function(req, res){
db.all("SELECT * FROM f11", function(err,rows){
rows.forEach(function (row) {
console.log('row: ' + row.GIVENNAME);
});
// console.log(rows);
res.render('form11.ejs',{array:rows});
});
};

I see you are using sqlite3 npm package for sqlite.
After looking at your code, You can try this to achieve what you want:
change get route to have a param id like this in your server.js
app.get('/legone/survey/surveyform/form11/:id', form11.get);
And, write your get function like this:
exports.get = function(req,res){
var id = req.params.id;
db.all("SELECT * FROM f11 WHERE id = ?",id, function(err,rows){
rows.forEach(function (row) {
console.log('row: ' + row.GIVENNAME);
});
res.render('form11.ejs',{array:rows});
});
};
And your route will be something like this:
http://localhost/legone/survey/surveyform/form11/23
where 23 is the id. Put whatever you want in its place.
if you are using ajax calls, it will look like this:
$http.get('/legone/survey/surveyform/form11/23')
.success(function(response){
//handle response
})
.error(function(error){
//handle error
});
you can test the route via POSTMAN or something like that.
For more information, you can Read Sqlite3 Wiki API Documentation or, directly about params and Callbacks here.
Also, after looking at your code you need lot of restructuring. You should define all your routes in one file and then use it inside app.js.
Something like this :
//define all the routes that start from '/legone/survey/surveyform' in one file
//(let it be 'surveryRoutes.js')
//and then include it in your app.js.
var surveyRoutes = require(./routes/surveyRoutes);
app.use('/legone/survey/surveyform',surveyRoutes);

If you want to get an id and query on that then:
First you'll need to pass an id in the request query. Like http://localhost/api/getUser?id=23
exports.getUser = function(req, res){
var user_id = req.query.id;
db.all("SELECT * FROM f11 WHERE id="+user_id, function(err,row){
console.log(row); // Since you'll only get one row
res.render('form11_detail.ejs',{data:row});
});
};
If you add this code then for displaying only one you could use 'getUser' function and for displaying all data, you could use your 'get' function.