I need to call a method after get the data from the http post request
service: request.service.TS
get_categories(number){
this.http.post( url, body, {headers: headers, withCredentials:true})
.subscribe(
response => {
this.total = response.json();
}, error => {
}
);
}
component: categories.TS
search_categories() {
this.get_categories(1);
//I need to call a Method here after get the data from response.json() !! e.g.: send_catagories();
}
Only works if I change to:
service: request.service.TS
get_categories(number){
this.http.post( url, body, {headers: headers, withCredentials:true})
.subscribe(
response => {
this.total = response.json();
this.send_catagories(); //here works fine
}, error => {
}
);
}
But I need to call the method send_catagories() inside of component after call this.get_categories(1); like this
component: categories.TS
search_categories() {
this.get_categories(1);
this.send_catagories(response);
}
What I doing wrong?
This question is related to
javascript
angular
typescript
promise
subscribe
Update your get_categories() method to return the total (wrapped in an observable):
// Note that .subscribe() is gone and I've added a return.
get_categories(number) {
return this.http.post( url, body, {headers: headers, withCredentials:true})
.map(response => response.json());
}
In search_categories(), you can subscribe the observable returned by get_categories() (or you could keep transforming it by chaining more RxJS operators):
// send_categories() is now called after get_categories().
search_categories() {
this.get_categories(1)
// The .subscribe() method accepts 3 callbacks
.subscribe(
// The 1st callback handles the data emitted by the observable.
// In your case, it's the JSON data extracted from the response.
// That's where you'll find your total property.
(jsonData) => {
this.send_categories(jsonData.total);
},
// The 2nd callback handles errors.
(err) => console.error(err),
// The 3rd callback handles the "complete" event.
() => console.log("observable complete")
);
}
Note that you only subscribe ONCE, at the end.
Like I said in the comments, the .subscribe() method of any observable accepts 3 callbacks like this:
obs.subscribe(
nextCallback,
errorCallback,
completeCallback
);
They must be passed in this order. You don't have to pass all three. Many times only the nextCallback is implemented:
obs.subscribe(nextCallback);
You can do this be using a new Subject too:
Typescript:
let subject = new Subject();
get_categories(...) {
this.http.post(...).subscribe(
(response) => {
this.total = response.json();
subject.next();
}
);
return subject; // can be subscribed as well
}
get_categories(...).subscribe(
(response) => {
// ...
}
);
You can code as a lambda expression as the third parameter(on complete) to the subscribe method. Here I re-set the departmentModel variable to the default values.
saveData(data:DepartmentModel){
return this.ds.sendDepartmentOnSubmit(data).
subscribe(response=>this.status=response,
()=>{},
()=>this.departmentModel={DepartmentId:0});
}
get_categories(number){
return this.http.post( url, body, {headers: headers, withCredentials:true})
.map(t=> {
this.total = t.json();
return total;
}).share();
);
}
then
this.get_category(1).subscribe(t=> {
this.callfunc();
});
You can add a callback function to your list of get_category(...) parameters.
Ex:
get_categories(number, callback){
this.http.post( url, body, {headers: headers, withCredentials:true})
.subscribe(
response => {
this.total = response.json();
callback();
}, error => {
}
);
}
And then you can just call get_category(...) like this:
this.get_category(1, name_of_function);
Source: Stackoverflow.com