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Add key to array of objects in async function [duplicate]

This question already has answers here:
Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference
(7 answers)
Closed 11 months ago.
I have an api route that needs to take data from two sources, merge the data together into one object and then return. The issue I am having is I'm basically stuck in async/await hell and when pushing to a second array within the .then() block, the second array named
clone returns []. How can I make an api request, merge the data and return to the requester as needed?
Fetch code:
export default async function getProduct(product_id) {
const product = await fetch(
`${process.env.PRIVATE_APP_URL}/products/${product_id}.json`,
{
method: "GET",
headers: {
"Content-Type": "application/json",
},
}
).then((result) => {
return result.json();
});
return product.product;
}
API Handler:
const recharge_subscription_res = await rechargeAPI(
"GET",
`https://api.rechargeapps.com/subscriptions?customer_id=${recharge_customer.id}`
);
const closest_array = recharge_subscription_res.subscriptions.filter(
(e) => e.next_charge_scheduled_at == closest_date
);
let clone = [];
closest_array.forEach((element) => {
getProduct(element.shopify_product_id).then((product) => {
element.shopify_product_handle = product.handle;
element.shopify_product_image_url = product.image.src;
clone.push(element);
});
});
console.log(clone);
clone should log as an array of objects like closest_array, but instead logs as just an empty array. This isn't exactly like the other seemingly duplicate questions because typically their feature doesn't require sending the promise's data back to an external source. Most questions are related to the front end of things. My situation is with an Express.js API. Any help would be appreciated.

The original promise spec used .then(), and the new syntax hides then's with await. Style-wise, it makes sense to choose just one style and go with it.
In either style, there's a little challenge having to do with creating many promises in a loop. The js iteration functions (like map and forEach) take synchronous functions. The most common design is to create a collection of promises in a synchronous loop, then run them concurrently with Promise.all(). Taking both ideas into account...
You could (but don't have to) rewrite your network request like this...
// since we decorated "async" let's use await...
export default async function getProduct(product_id) {
const url = `${process.env.PRIVATE_APP_URL}/products/${product_id}.json`;
const options = { method: "GET", headers: { "Content-Type": "application/json" }};
const result = await fetch(url, options);
const product = await result.json();
return product.product;
}
await is not permitted at the top-level; it may be used only within an async function. Here, I'll make up a name and guess about the parameter
async function rechargeAndLookupProduct(recharge_customer) {
const base = 'https://api.rechargeapps.com/subscriptions';
const query = `customer_id=${recharge_customer.id}`;
const recharge_subscription_res = await rechargeAPI("GET",`${base}?${query}`);
const closest_array = recharge_subscription_res.subscriptions.filter(e =>
e.next_charge_scheduled_at == closest_date
);
// here's the important part: collect promises synchronously
// execute them together with Promise.all()
const promises = closest_array.map(element => {
return getProduct(element.shopify_product_id)
});
const allProducts = await Promise.all(promises);
// allProducts will be an array of objects that the promises resolved to
const clones = allProducts.map((product, i) => {
// use Object.assign so we'll really have a "clone"
let closest = Object.assign({}, closest_array[i]);
closest.shopify_product_handle = product.handle;
closest.shopify_product_image_url = product.image.src;
return closest;
});
// if I didn't make any typos (which I probably did), then
// clones ought to contain the result you expect
console.log(clones);
}

Your code has a flaw (in the section shown below). You have a dangling promise that you forgot to await or return.
When you log clone, none of the async getProduct operations have completed yet, and none of the elements have been pushed.
let clone = [];
closest_array.forEach((element) => {
getProduct(element.shopify_product_id).then((product) => {
element.shopify_product_handle = product.handle;
element.shopify_product_image_url = product.image.src;
clone.push(element);
}); // FLAW: dangling .then
});
console.log(clone); // FLAW: clone is not ready yet.
I would set it up more like this:
let clone = await Promise.all(closest_array.map((element) =>
getProduct(element.shopify_product_id).then((product) => {
element.shopify_product_handle = product.handle;
element.shopify_product_image_url = product.image.src;
return element;
})
));
console.log(clone);
It's a little sketchy to modify element the way you are (I wouldn't), but this way the getProduct calls are all in flight together for maximum efficiency. Promise.all handles awaiting all the promises and putting each's result into an array of results, which you can then await as a single promise since the calling function is async.

Array of filtered axios results from paginated API is empty

In my code below I get an empty array on my console.log(response) but the console.log(filterdIds) inside the getIds function is showing my desired data. I think my resolve is not right.
Note that I run do..while once for testing. The API is paged. If the records are from yesterday it will keep going, if not then the do..while is stopped.
Can somebody point me to the right direction?
const axios = require("axios");
function getToken() {
// Get the token
}
function getIds(jwt) {
return new Promise((resolve) => {
let pageNumber = 1;
const filterdIds = [];
const config = {
//Config stuff
};
do {
axios(config)
.then((response) => {
response.forEach(element => {
//Some logic, if true then:
filterdIds.push(element.id);
console.log(filterdIds);
});
})
.catch(error => {
console.log(error);
});
} while (pageNumber != 1)
resolve(filterdIds);
});
}
getToken()
.then(token => {
return token;
})
.then(jwt => {
return getIds(jwt);
})
.then(response => {
console.log(response);
})
.catch(error => {
console.log(error);
});
I'm also not sure where to put the reject inside the getIds function because of the do..while.

The fundamental problem is that resolve(filterdIds); runs synchronously before the requests fire, so it's guaranteed to be empty.
Promise.all or Promise.allSettled can help if you know how many pages you want up front (or if you're using a chunk size to make multiple requests--more on that later). These methods run in parallel. Here's a runnable proof-of-concept example:
const pages = 10; // some page value you're using to run your loop
axios
.get("https://httpbin.org") // some initial request like getToken
.then(response => // response has the token, ignored for simplicity
Promise.all(
Array(pages).fill().map((_, i) => // make an array of request promisess
axios.get(`https://jsonplaceholder.typicode.com/comments?postId=${i + 1}`)
)
)
)
.then(responses => {
// perform your filter/reduce on the response data
const results = responses.flatMap(response =>
response.data
.filter(e => e.id % 2 === 0) // some silly filter
.map(({id, name}) => ({id, name}))
);
// use the results
console.log(results);
})
.catch(err => console.error(err))
;
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
The network tab shows the requests happening in parallel:
If the number of pages is unknown and you intend to fire requests one at a time until your API informs you of the end of the pages, a sequential loop is slow but can be used. Async/await is cleaner for this strategy:
(async () => {
// like getToken; should handle err
const tokenStub = await axios.get("https://httpbin.org");
const results = [];
// page += 10 to make the snippet run faster; you'd probably use page++
for (let page = 1;; page += 10) {
try {
const url = `https://jsonplaceholder.typicode.com/comments?postId=${page}`;
const response = await axios.get(url);
// check whatever condition your API sends to tell you no more pages
if (response.data.length === 0) {
break;
}
for (const comment of response.data) {
if (comment.id % 2 === 0) { // some silly filter
const {name, id} = comment;
results.push({name, id});
}
}
}
catch (err) { // hit the end of the pages or some other error
break;
}
}
// use the results
console.log(results);
})();
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
Here's the sequential request waterfall:
A task queue or chunked loop can be used if you want to increase parallelization. A chunked loop would combine the two techniques to request n records at a time and check each result in the chunk for the termination condition. Here's a simple example that strips out the filtering operation, which is sort of incidental to the asynchronous request issue and can be done synchronously after the responses arrive:
(async () => {
const results = [];
const chunk = 5;
for (let page = 1;; page += chunk) {
try {
const responses = await Promise.all(
Array(chunk).fill().map((_, i) =>
axios.get(`https://jsonplaceholder.typicode.com/comments?postId=${page + i}`)
)
);
for (const response of responses) {
for (const comment of response.data) {
const {name, id} = comment;
results.push({name, id});
}
}
// check end condition
if (responses.some(e => e.data.length === 0)) {
break;
}
}
catch (err) {
break;
}
}
// use the results
console.log(results);
})();
<script src="https://unpkg.com/axios/dist/axios.min.js"></script>
(above image is an except of the 100 requests, but the chunk size of 5 at once is visible)
Note that these snippets are proofs-of-concept and could stand to be less indiscriminate with catching errors, ensure all throws are caught, etc. When breaking it into sub-functions, make sure to .then and await all promises in the caller--don't try to turn it into synchronous code.
See also
How do I return the response from an asynchronous call? and Why is my variable unaltered after I modify it inside of a function? - Asynchronous code reference which explain why the array is empty.
What is the explicit promise construction antipattern and how do I avoid it?, which warns against adding a new Promise to help resolve code that already returns promises.

To take a step back and think about why you ran into this issue, we have to think about how synchronous and asynchronous javascript code works together. Your
synchronous getIds function is going to run to completion, stepping through each line until it gets to the end.
The axios function invocation is returning a Promise, which is an object that represents some future fulfillment or rejection value. That Promise isn't going to resolve until the next cycle of the event loop (at the earliest), and your code is telling it to do some stuff when that pending value is returned (which is the callback in the .then() method).
But your main getIds function isn't going to wait around... it invokes the axios function, gives the Promise that is returned something to do in the future, and keeps going, moving past the do/while loop and onto the resolve method which returns a value from the Promise you created at the beginning of the function... but the axios Promise hasn't resolved by that point and therefore filterIds hasn't been populated.
When you moved the resolve method for the promise you're creating into the callback that the axios resolved Promise will invoke, it started working because now your Promise waits for axios to resolve before resolving itself.
Hopefully that sheds some light on what you can do to get your multi-page goal to work.
I couldn't help thinking there was a cleaner way to allow you to fetch multiple pages at once, and then recursively keep fetching if the last page indicated there were additional pages to fetch. You may still need to add some additional logic to filter out any pages that you batch fetch that don't meet whatever criteria you're looking for, but this should get you most of the way:
async function getIds(startingPage, pages) {
const pagePromises = Array(pages).fill(null).map((_, index) => {
const page = startingPage + index;
// set the page however you do it with axios query params
config.page = page;
return axios(config);
});
// get the last page you attempted, and if it doesn't meet whatever
// criteria you have to finish the query, submit another batch query
const lastPage = await pagePromises[pagePromises.length - 1];
// the result from getIds is an array of ids, so we recursively get the rest of the pages here
// and have a single level array of ids (or an empty array if there were no more pages to fetch)
const additionalIds = !lastPage.done ? [] : await getIds(startingPage + pages, pages);
// now we wait for all page queries to resolve and extract the ids
const resolvedPages = await Promise.all(pagePromises);
const resolvedIds = [].concat(...resolvedPages).map(elem => elem.id);
// and finally merge the ids fetched in this methods invocation, with any fetched recursively
return [...resolvedIds, ...additionalIds];
}

Handle dynamic number of promises in Node Js

I'm fetching product's data from a bunch of URLs. The result of these promises (along with product details) may contain a key called nextPage, which has a URL as value. I need to fetch data from that URL too. How can I wait for all the original set of promises + dynamic promises attached based on nextPage key ?
Currently I'm trying the following:
const allUrls = ['url1', 'url2', 'url3'];
const promiseArray = [];
const getData = (url) => {
const p = axios.get(url).then((data) => {
if (data.nextPage) {
// Push this into promises so that the data is not lost
promiseArray.push(Promise.resolve(data));
// There are more pages to fetch data from
return getData(data.nextPage);
}
// No further pages, so return the result
return data;
});
return p;
}
allUrls.forEach((url) => {
const p = getData(url);
promiseArray.push(p);
});
Promise.all(promiseArray).then((data) => {
// Error: data only has the value of allUrls, not dynamically added data
})
As I have put a comment, when the Promise.all resolves, I only get the data of original URLs put in allUrls, not the dynamically added promises.

The problem is that by the time Promise.all is executed, promiseArray will only contain the promises for the product's data, not the details. You'd need to await each product data promise, and then push the resulting promise to the array (note that I'm using async/await as it allows for cleaner code):
for (const url of allUrls) {
const p = await getData(url);
promiseArray.push(p);
}
const result = await Promise.all(promiseArray);
console.log(result);

'getDownloadURL' returns one less URL in a Promise

I'm trying to upload several pictures to Firebase Storage and get their URLs to add these as a field in a gym's profile. However, with the code I came up with, always one URL is not returned. If I upload 3 pictures, 3 pictures appear in Storage but I only get 2 URLs. How do I fix that?
const promises = [];
const URLarray = [];
imageAsFile.forEach(img => {
const uploadTask = storage.ref().child(`/photos/${doc.id}/${img.name}`).put(img);
promises.push(uploadTask);
uploadTask.then((uploadTaskSnapshot) => {
return uploadTaskSnapshot.ref.getDownloadURL();
}).then((pic) => {
const addPics = db.collection("gyms").doc(doc.id)
promises.push(addPics);
addPics.update({gymPhoto: firebase.firestore.FieldValue.arrayUnion(pic)});
// URLarray.push(pic)
})
});
Promise.all(promises).then(() => {
// console.log(URLarray)
alert("Done");
})

The following should work (untested):
const promises = [];
imageAsFile.forEach(img => {
const uploadTask = storage.ref().child(`/photos/${doc.id}/${img.name}`).put(img);
promises.push(uploadTask);
});
Promise.all(promises)
.then(uploadTaskSnapshotsArray => {
const promises = [];
uploadTaskSnapshotsArray.forEach(uploadTaskSnapshot => {
promises.push(uploadTaskSnapshot.ref.getDownloadURL());
});
return Promise.all(promises);
})
.then(urlsArray => {
const docRef = db.collection("gyms").doc(doc.id);
return docRef.update({ gymPhoto: firebase.firestore.FieldValue.arrayUnion(...urlsArray) });
})
Promise.all() returns a single promise: This promise is fulfilled with an Array containing all the resolved values in the Array passed as the argument.
So, if you call Promise.all() with the Array of uploadTasks, when the returned promise is fulfilled you will get an Array of uploadTaskSnapshots.
Then you need to use this Array to get an Array of URLs, again by using Promise.all().
Then, when you get the Array of URLs, you need to update only once the document with id = doc.id. So here you don't need Promise.all(). What you need to do is to pass several values to the FieldValue.arrayUnion() method. For that you need to use the Spread operator, as follows:
docRef.update({ gymPhoto: firebase.firestore.FieldValue.arrayUnion(...urlsArray) });

Using promise in loop results in Promise failure

I'd like to reuse the same code in a loop. This code contains promises. However, when iterating, this code results in an error.
I've tried using for and while loops. There seems to be no issue when I use the for loop for a single iteration.
Here is a minimal version of my code:
var search_url = /* Some initial URL */
var glued = "";
for(var i = 0; i < 2; i++)
{
const prom = request(search_url)
.then(function success(response /* An array from a XMLHTTPRequest*/) {
if (/* Some condition */)
{
search_url = /* Gets next URL */
glued += processQuery(response[0]);
} else {
console.log("Done.")
}
})
.catch(function failure(err) {
console.error(err.message); // TODO: do something w error
})
}
document.getElementById('api-content').textContent = glued;
I expect the results to append to the variable glued but instead, I get an error: failure Promise.catch (async) (anonymous) after the first iteration of the loop.

Answer:
You can use the Symbol.iterator in accordance with for await to perform asynchronous execution of your promises. This can be packaged up into a constructor, in the example case it's called Serial (because we're going through promises one by one, in order)
function Serial(promises = []) {
return {
promises,
resolved: [],
addPromise: function(fn) {
promises.push(fn);
},
resolve: async function(cb = i => i, err = (e) => console.log("trace: Serial.resolve " + e)) {
try {
for await (let p of this[Symbol.iterator]()) {}
return this.resolved.map(cb);
} catch (e) {
err(e);
}
},
[Symbol.iterator]: async function*() {
this.resolved = [];
for (let promise of this.promises) {
let p = await promise().catch(e => console.log("trace: Serial[Symbol.iterator] ::" + e));
this.resolved.push(p);
yield p;
}
}
}
}
What is the above?
It's a constructor called Serial.
It takes as an argument an array of Functions that return Promises.
The functions are stored in Serial.promises
It has an empty array stored in Serial.resolved - this will store the resolved promise requests.
It has two methods:
addPromise: Takes a Function that returns a Promise and adds it to Serial.promises
resolve: Asynchronously calls a custom Symbol.iterator. This iterator goes through every single promise, waits for it to be completed, and adds it to Serial.resolved. Once this is completed, it returns a map function that acts on the populated Serial.resolved array. This allows you to simply call resolve and then provide a callback of what to do with the array of responses. A.e. .resolve()((resolved_requests) => //do something with resolved_requests)
Why does it work?
Although many people don't realize this Symbol.iterator is much more powerful than standard for loops. This is for two big reasons.
The first reason, and the one that is applicable in this situation, is because it allows for asynchronous calls that can affect the state of the applied object.
The second reason is that it can be used to provide two different types of data from the same object. A.e. You may have an array that you would like to read the contents of:
let arr = [1,2,3,4];
You can use a for loop or forEach to get the data:
arr.forEach(v => console.log(v));
// 1, 2, 3, 4
But if you adjust the iterator:
arr[Symbol.iterator] = function* () {
yield* this.map(v => v+1);
};
You get this:
arr.forEach(v => console.log(v));
// 1, 2, 3, 4
for(let v of arr) console.log(v);
// 2, 3, 4, 5
This is useful for many different reasons, including timestamping requests/mapping references, etc. If you'd like to know more please take a look at the ECMAScript Documentation: For in and For Of Statements
Use:
It can be used by calling the constructor with an Array of functions that return Promises. You can also add Function Promises to the Object by using
new Serial([])
.addPromise(() => fetch(url))
It doesn't run the Function Promises until you use the .resolve method.
This means that you can add promises ad hoc if you'd like before you do anything with the asynchronous calls. A.e. These two are the same:
With addPromise:
let promises = new Serial([() => fetch(url), () => fetch(url2), () => fetch(url3)]);
promises.addPromise(() => fetch(url4));
promises.resolve().then((responses) => responses)
Without addPromise:
let promises = new Serial([() => fetch(url), () => fetch(url2), () => fetch(url3), () => fetch(url4)])
.resolve().then((responses) => responses)
Data:
Since I can't really replicate your data calls, I opted for JSONPlaceholder (a fake online rest api) to show the promise requests in action.
The data looks like this:
let searchURLs = ["https://jsonplaceholder.typicode.com/todos/1",
"https://jsonplaceholder.typicode.com/todos/2",
"https://jsonplaceholder.typicode.com/todos/3"]
//since our constructor takes functions that return promises, I map over the URLS:
.map(url => () => fetch(url));
To get the responses we can call the above data using our constructor:
let promises = new Serial(searchURLS)
.resolve()
.then((resolved_array) => console.log(resolved_array));
Our resolved_array gives us an array of XHR Response Objects. You can see that here:
function Serial(promises = []) {
return {
promises,
resolved: [],
addPromise: function(fn) {
promises.push(fn);
},
resolve: async function(cb = i => i, err = (e) => console.log("trace: Serial.resolve " + e)) {
try {
for await (let p of this[Symbol.iterator]()) {}
return this.resolved.map(cb);
} catch (e) {
err(e);
}
},
[Symbol.iterator]: async function*() {
this.resolved = [];
for (let promise of this.promises) {
let p = await promise().catch(e => console.log("trace: Serial[Symbol.iterator] ::" + e));
this.resolved.push(p);
yield p;
}
}
}
}
let searchURLs = ["https://jsonplaceholder.typicode.com/todos/1", "https://jsonplaceholder.typicode.com/todos/2", "https://jsonplaceholder.typicode.com/todos/3"].map(url => () => fetch(url));
let promises = new Serial(searchURLs).resolve().then((resolved_array) => console.log(resolved_array));
Getting Results to Screen:
I opted to use a closure function to simply add text to an output HTMLElement.
This is added like this:
HTML:
<output></output>
JS:
let output = ((selector) => (text) => document.querySelector(selector).textContent += text)("output");
Putting it together:
If we use the output snippet along with our Serial object the final functional code looks like this:
let promises = new Serial(searchURLs).resolve()
.then((resolved) => resolved.map(response =>
response.json()
.then(obj => output(obj.title))));
What's happening above is this:
we input all our functions that return promises. new Serial(searchURLS)
we tell it to resolve all the requests .resolve()
after it resolves all the requests, we tell it to take the requests and map the array .then(resolved => resolved.map
the responses we turn to objects by using .json method. This is necessary for JSON, but may not be necessary for you
after this is done, we use .then(obj => to tell it to do something with each computed response
we output the title to the screen using output(obj.title)
Result:
let output = ((selector) => (text) => document.querySelector(selector).textContent += text)("output");
function Serial(promises = []) {
return {
promises,
resolved: [],
addPromise: function(fn) {
promises.push(fn);
},
resolve: async function(cb = i => i, err = (e) => console.log("trace: Serial.resolve " + e)) {
try {
for await (let p of this[Symbol.iterator]()) {}
return this.resolved.map(cb);
} catch (e) {
err(e);
}
},
[Symbol.iterator]: async function*() {
this.resolved = [];
for (let promise of this.promises) {
let p = await promise().catch(e => console.log("trace: Serial[Symbol.iterator] ::" + e));
this.resolved.push(p);
yield p;
}
}
}
}
let searchURLs = ["https://jsonplaceholder.typicode.com/todos/1", "https://jsonplaceholder.typicode.com/todos/2", "https://jsonplaceholder.typicode.com/todos/3"].map(url => () => fetch(url));
let promises = new Serial(searchURLs).resolve()
.then((resolved) => resolved.map(response =>
response.json()
.then(obj => output(obj.title))));
<output></output>
Why go this route?
It's reusable, functional, and if you import the Serial Constructor you can keep your code slim and comprehensible. If this is a cornerstone of your code, it'll be easy to maintain and use.
Using it with your code:
I will add how to specifically use this with your code to fully answer your question and so that you may understand further.
NOTE glued will be populated with the requested data, but it's unnecessary. I left it in because you may have wanted it stored for a reason outside the scope of your question and I don't want to make assumptions.
//setup urls:
var search_urls = ["https://jsonplaceholder.typicode.com/todos/1", "https://jsonplaceholder.typicode.com/todos/2"];
var request = (url) => () => fetch(url);
let my_requests = new Serial(search_urls.map(request));
//setup glued (you don't really need to, but if for some reason you want the info stored...
var glued = "";
//setup helper function to grab title(this is necessary for my specific data)
var addTitle = (req) => req.json().then(obj => (glued += obj.title, document.getElementById('api-content').textContent = glued));
// put it all together:
my_requests.resolve().then(requests => requests.map(addTitle));
Using it with your code - Working Example:
function Serial(promises = []) {
return {
promises,
resolved: [],
addPromise: function(fn) {
promises.push(fn);
},
resolve: async function(cb = i => i, err = (e) => console.log("trace: Serial.resolve " + e)) {
try {
for await (let p of this[Symbol.iterator]()) {}
return this.resolved.map(cb);
} catch (e) {
err(e);
}
},
[Symbol.iterator]: async function*() {
this.resolved = [];
for (let promise of this.promises) {
let p = await promise().catch(e => console.log("trace: Serial[Symbol.iterator] ::" + e));
this.resolved.push(p);
yield p;
}
}
}
}
//setup urls:
var search_urls = ["https://jsonplaceholder.typicode.com/todos/1", "https://jsonplaceholder.typicode.com/todos/2"];
var request = (url) => () => fetch(url);
let my_requests = new Serial(search_urls.map(request));
//setup glued (you don't really need to, but if for some reason you want the info stored...
var glued = "";
//setup helper function to grab title(this is necessary for my specific data)
var addTitle = (req) => req.json().then(obj => (glued += obj.title, document.getElementById('api-content').textContent = glued));
// put it all together:
my_requests.resolve().then(requests => requests.map(addTitle));
<div id="api-content"></div>
Final Note
It's likely that we will be seeing a prototypal change to the Promise object in the future that allows for easy serialization of Promises. Currently (7/15/19) there is a TC39 Proposal that does add a lot of functionality to the Promise object but it hasn't been fully vetted yet, and as with many ideas trapped within the Proposal stage, it's almost impossible to tell when they will be implemented into Browsers, or even if the idea will stagnate and fall off the radar.
Until then workarounds like this are necessary and useful( the reason why I even went through the motions of constructing this Serializer object was for a transpiler I wrote in Node, but it's been very helpful beyond that! ) but do keep an eye out for any changes because you never know!
Hope this helps! Happy Coding!

Your best bet is probably going to be building up that glued variable with recursion.
Here's an example using recursion with a callback function:
var glued = "";
requestRecursively(/* Some initial URL string */, function() {
document.getElementById('api-content').textContent = glued;
});
function requestRecursively(url, cb) {
request(url).then(function (response) {
if (/* Some condition */) {
glued += processQuery(response[0]);
var next = /* Gets next URL string */;
if (next) {
// There's another URL. Make another request.
requestRecursively(next, cb);
} else {
// We're done. Invoke the callback;
cb();
}
} else {
console.log("Done.");
}
}).catch(function (err) {
console.error(err.message);
});
}