CODEWITHSUNDEEP
javascriptfunctiongoogle-maps-api-3asynccallback
Nicky Larson
Nicky Larson

Reputation: 43

Callback function not working as expected

I'm having difficulties to write a callback function to get a values from an asynchronous request made by google direction api, what I need here is to write a callback function that will get me the time when asynchronous request has completed. I wanted to do it by myself but i just don't understand why is it not working, following some examples that I've seen on this site this should be working.

here is my callback function 

function getTime(myVar){alert(myVar);}

the function where the callback function is being called 

function travellingTime(Origin, Destination, callback) {
    var myVar;
    var directionsService = new google.maps.DirectionsService();
    var request = {
        origin: Origin,
        destination: Destination,
        travelMode: google.maps.DirectionsTravelMode.DRIVING
    };

    directionsService.route(request, function (response, status) {
        if (status == google.maps.DirectionsStatus.OK) {
            // Display the distance:
            //alert(response.routes[0].legs[0].distance.value + " meters");
            // Display the duration:
            //Time = (response.routes[0].legs[0].duration.value / 60);

            myVar = (response.routes[0].legs[0].duration.value / 60);
            callback(myVar);
        }
    });
}

triggering action on button 

<button onclick="travellingTime('portlouis','vacoas',getTime())">TSP</button>

I'm still getting myVar as undefined when alert

Upvotes: 1

Views: 231

Answers (1)

Abinash Gupta
Abinash Gupta

Reputation: 321

You are calling getTime and passing the result, just pass it without calling it.Like so(remove the pair of parenthesis).

<button onclick="travellingTime('port louis','vacoas',getTime)">TSP</button>

Upvotes: 1

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