I have http.get and it's impossible for me to create array of objects. Can you help me ? I need to create loop on array of returned objects and i can't do this.
export class Link {
idStat: String;
idAccount: String;
}
links: Link [];
router.get('/linkGetAll', function(req, res, next) {
Link.find(function (err, products) {
if (err) return next(err);
res.json(products);
});
});
getAllLinks(){
return this.http.get('/main/linkGetAll');
}
this.api.getAllLinks().subscribe((data) => {
this.links = data;
})
for(let item in this.links)
{
DOESN'T WORK
}
getAllLinks(){
return this.http.get('/main/linkGetAll')
.pipe(map(res => {
// do something here
// res.forEach() or res.map()
return 'it';
})
);
}
Before going to
for(let item in this.links)
{
DOESN'T WORK
}
Ensure that this.links has data in it.(use async/await along with toPromise())
Please read this section about HTTP of the Angular tutorial and the Angular API.
The get method accepts a type:
get<T>(...): Observable<T>
so you could modify your implementation of getAllLinks:
getAllLinks(): Observable<Link[] {
return this.http.get<Link[]>('/main/linkGetAll');
}
Now you should should be able to iterate the response:
getAllLinks().subscribe(links => {
links.forEach(link => // do what you need);
}
Related
I am trying to run some API calls in parallel, but am having problems since I am trying to call a function again before the API data has been returned.
I am thinking that I could possibly use the new command in Node, but am not sure how to structure it into this scheme. I am trying to avoid recursion, as I already have a recursive version working and it is slow.
Currently I am trying to this code on the server.
loopThroughArray(req, res) {
for(let i=0; i<req.map.length; i++) {
stack[i] = (callback) => {
let data = getApi(req, res, req.map[i], callback)
}
}
async.parallel(stack, (result) => {
res.json(result)
})
}
....
function getApi(req, res, num, cb) {
request({
url: 'https://example.com/api/' + num
},
(error, response, body) => {
if(error) {
// Log error
} else {
let i = {
name: JSON.parse(body)['name'],
age: '100'
}
console.log(body) // Returns empty value array.length > 1 (req.map[i])
cb(i)
}
})
Is there a way to spawn new instances of the function each time it's called and accumulate the results to send back as one result to the client?
Here's an example of calling Web APIs (each with different parameters), using the Async library, we start by creating an array of N function variables.
const async = require('async');
const request = require('request');
//Set whatever request options you like, see: https://github.com/request/request#requestoptions-callback
var requestArray = [
{url: 'https://httpbin.org/get'},
{url: 'https://httpbin.org/ip'}
];
let getApi = function (opt, callback) {
request(opt, (err, response, body) => {
callback(err, JSON.parse(body));
});
};
const functionArray = requestArray.map((opt) => {
return (callback) => getApi(opt, callback);
});
async.parallel(
functionArray, (err, results) => {
if (err) {
console.error('Error: ', err);
} else {
console.log('Results: ', results.length, results);
}
});
You can easily switch the Url and Query values to match whatever you need. I'm using HttpBin here, since it's good for illustrative purposes.
I have the following method which isn't working correct:
getProducts(): Observable<Product[]> {
let PRODUCTS: Product[];
this.http.get(this.base_url + "api/products")
.subscribe(
(data) => {
for(var i in data) {
PRODUCTS.push(new Product(data[i].id, data[i].name, data[i].category, data[i].description, data[i].price, data[i].amount));
}
},
(error) => {
console.log(error);
});
return of(PRODUCTS);
}
The error I'm getting is this:
TypeError: Cannot read property 'push' of undefined
Now, I know that the PRODUCT array is not accessable from within the subscribe function, but I cannot get the correct solution for it.
Can anyone help me with that. I want to return an Observable<Product[]>.
Thank you in advance!
Edit: Updated to account for the fact that the API seems to return an array-like object rather than a true array.
You want to use map:
getProducts(): Observable<Product[]> {
return this.http.get(this.base_url + "api/products")
.map(data => {
let products = [];
for (let i in data) {
products.push(new Product(data[i].id, data[i].name, data[i].category, data[i].description, data[i].price, data[i].amount));
}
return products;
})
.do(null, console.log);
}
Since #pixelbit's comment keeps getting upvotes despite being wrong, here's an example showing why it is wrong:
// Fakes a HTTP call which takes half a second to return
const api$ = Rx.Observable.of([1, 2, 3]).delay(500);
function getProducts() {
let products = [];
api$.subscribe(data => {
for (let i in data) {
products.push(data[i]);
}
});
return Rx.Observable.of(products);
}
// Logs '[]' instead of '[1, 2, 3]'
getProducts().subscribe(console.log);
I just created a NodeJS cloudantDB web starter on bluemix. Then, I have a API get data from cloudantDB and get successfull but it returns all data. Please see js file:
js file:
app.get('/api/provider', function(request, response) {
console.log("Get method invoked.. ")
db = cloudant.use(dbCredentials.dbProvider);
var docList = [];
var i = 0;
db.list(function(err, body) {
if (!err) {
var len = body.rows.length;
console.log('total # of docs -> '+len);
if(len == 0) {
// error
} else {
body.rows.forEach(function(document) {
db.get(document.id, { revs_info: true }, function(err, doc) {
if (!err) {
if(doc['_attachments']) {
// todo
} else {
var responseData = createResponseDataProvider(
doc._id,
doc.provider_type,
doc.name,
doc.phone,
doc.mobile,
doc.email,
doc.logo,
doc.address
);
}
docList.push(responseData);
i++;
if(i >= len) {
response.write(JSON.stringify(docList));
console.log('ending response...');
response.end();
}
} else {
console.log(err);
}
});
});
}
} else {
console.log(err);
}
});
If I want to add parameter to API to get specific data from DB , Do we need create search index or query on cloudant, afer that call API the same : app.get('/api/provider/:id'). Please help me review and sharing. Thanks
you could get the document by id/name:
db.get(docID, function(err, data) {
// do something
});
references:
https://github.com/apache/couchdb-nano#document-functions
https://github.com/cloudant/nodejs-cloudant#api-reference
You can use a search function of Cloudant.
You need to create search index. In search index you can manage what data you want to get.
Example: https://cloudant.com/for-developers/search/
Following this code after create search index.
...
var query = {q: "id:doc.id"};
db.search('design document name', 'index name', query, function(er, result) {
if (er) {
throw er;
}
console.log(result);
});
I have an emails object that contains an array in a mongodb database. However, when I try to use $set to make the array empty it doesn't work. How am I supposed to clear the array?
exports.clearEmails = function(req, res, next) {
var listId = req.params.id;
var errors = req.validationErrors();
if (errors) {
return res.status(400).send(errors);
}
EmailList.update({'_id': listId}, {$set: {'emails': []}}, function(err,results) {
if (err) {
return res.status(400).send(err);
} else {
return res.status(200).send(results);
}
});
}
I'm pretty new to this type of programming and I'm having some trouble populating an array from a nested call. I'm pretty sure this needs to be done using callbacks, but I'm having trouble wrapping my brain around it. Closures must also come into play here. I tried searching the web for a similar example but didn't find much.
Here is my original code. I tried a few different approaches but didn't pull it off.
TaskSchema.statics.formatAssignee = function(assignees) {
var users = [];
assignees.forEach(function(uid) {
mongoose.model('User').findById(uid, function(err, user) {
users.push({
name: user.name.full
, id: user.id
});
});
});
return users;
}
I really like the following pattern (recursion is the most elegant solution to async loops):
TaskSchema.statics.formatAssignee = function(assignees, callback) {
var acc = []
, uids = assignees.slice()
(function next(){
if (!uids.length) return callback(null, acc);
var uid = uids.pop()
mongoose.model('User').findById(uid, function(err, user) {
if (err) return callback(err);
acc.push({
name: user.name.full
, id: user.id
});
next();
});
})();
}
Check out async, it has an async foreach loop.
Edit
Here is the foreach method from the async library
async.forEach = function (arr, iterator, callback) {
if (!arr.length) {
return callback();
}
var completed = 0;
_forEach(arr, function (x) {
iterator(x, function (err) {
if (err) {
callback(err);
callback = function () {};
}
else {
completed += 1;
if (completed === arr.length) {
callback();
}
}
});
});
};
var _forEach = function (arr, iterator) {
if (arr.forEach) {
return arr.forEach(iterator);
}
for (var i = 0; i < arr.length; i += 1) {
iterator(arr[i], i, arr);
}
};
you could do something like:
Give formatAssignee a callback.
Count down how many users you need to push onto users.
After you push the last one, invoke the callback with the parameter users.