Stop SetInterval once response from server is received

Ionic Framework ionic-v3
1

I need to check if a data response is sent from my server and then stop the SetInterval function. The server response will happen at a random time.

My SetInterval(() function continues to cycle through even once a data response from the server is received.

How can I stop SetInterval from firing once a data response is received? Or is there a better way to check if my server has sent a response? :sweat:


    ionViewDidEnter() {

          setInterval(() => {    
              let headers = new Headers();
              headers.append('Content-Type', 'application/json');
              let checkUserJson = 'http://localhost:9239/auth-received-check';

              var usernameData = JSON.stringify({username: this.username});

              this.http.post(checkUserJson, usernameData, {headers: headers})
                .map(res => res.json())
                .subscribe(data => {
                  console.log(data);
                }, error => {
                 console.log("could not get json data");
                });

          }, 5000); 
    }
2

Use clearInterval() function after get response from server. Check this link
https://www.w3schools.com/jsref/met_win_clearinterval.asp

1 Like
3

Absolutely. Look into the timeout operator.

5

So what are you really trying to achieve with setInterval?
Imho if you are just trying to make sure your code retries several times and on successful result stops - there are better patterns to achieve that, Can you share what is that you are trying to achieve?

6

Exactly what you just said - I have the setInverval in place so that it keeps retrying until it gets a successful result.

I have an external JSON file that will get created on a website, and then my nodejs server does a check to see if it can access the file - the post request in my iconic file (shown in initial post) checks the server to see if accessing the file was successful, and if so, the server returns a response.

So all the code is working, it’s just probably a dodgy solution on the ionic side…I must add that this won’t ever be production code and its purely for me playing around with, but I just wanted to get some advice on other methods I could use to achieve the above.

7

It sounds like you are trying to reinvent push notifications.

8

I ended up going with the clearInterval option suggested by @anandkumar100 as it was the quickest to implement.

I’m having errors with clearing the interval now though…

“Property ‘interval’ does not exist on type…”

Any suggestions? :slight_smile:


    ionViewDidEnter() {


         this.interval = setInterval(() => {
          
          console.log("Do stuff...")  

          }, 5000); 
    }


}

and then clearing the interval…

 public successMsg() {
      clearInterval(this.interval);
    
}
1 Like
9

Ok figured it out - I combined the clearInterval into the setInterval function. Maybe this might help someone in future who googles a simple function for setInterval and clearInterval in Ionic 3:

        let id = setInterval( () => {

          console.log("do stuff...")  

          if (some.condition = true) {
            clearInterval(id);
          }
        }, 5000);
1 Like
10

define interval above like
interval: number;