CODEWITHSUNDEEP
javascriptnode.jsasynchronoussettimeout
erwinnandpersad
erwinnandpersad

Reputation: 386

Node JS, run same function after it is finished

My applications need to poll every 2 seconds if there are changes. For now i use setInterval, but sometimes myFunction takes longer then 2 seconds to execute and records in the mysql database will be inserted twice. I make use of the async lib in myFunction..

So i need this...

When myFunction is finished

method.myFunction() =>

It needs to run again (but only when it is finished). setInterval with x seconds is not an option. This is because they can run at the same time if the scripts takes longer then x seconds.

How can i run myFunction again after x seconds, but only when myFunction is done with processing So in psuedo code it would be this

if method.myFunction == finished wait 2 seconds run method.myFunction again

Upvotes: 1

Views: 3086

Answers (3)

erwinnandpersad
erwinnandpersad

Reputation: 386

I used modified your code to this and it works like a charm...

var backup_timeout_seconds = 5000;
var main_rest_seconds = 2000;
function godMethod(timeout){


    var backuptimeout = setTimeout(function(){
        godMethod(main_rest_seconds);
        console.log("Called backup timeout, script is stuck...");
    }, backup_timeout_seconds);


    
    Pollforbids.pollForNewBids2(,function (err,res) {
        executor(timeout);
        clearTimeout(backuptimeout);
    });



}





function executor(interval){
    setTimeout(function(){
        godMethod(interval);
    }, interval);

}

godMethod(main_rest_seconds);

Upvotes: -2

Rahul Sharma
Rahul Sharma

Reputation: 356

Use callback or, even better, Promises to let next poll execute only when the previous process is completed.

Upvotes: 1

Prasanth Jaya
Prasanth Jaya

Reputation: 4736

so with the below code, your method will be called once every seconds when the function execution is over.

function godMethod(){
    /* do what ever you want but call executor once you are done with everything */
    someCallbackForInsertion(data, function(){
        executor()
    })      
}

function executor(){
    setInterval(function(){
        godMethod()
    }, 2000);   
}

executor();

So here you call the executor on start of the server, then after 2 seconds it calls the godMethod then do your insertion/whatever. After successfully inserted call the executor again.

Upvotes: 6

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