Welcome to the Treehouse Community

The Treehouse Community is a meeting place for developers, designers, and programmers of all backgrounds and skill levels to get support. Collaborate here on code errors or bugs that you need feedback on, or asking for an extra set of eyes on your latest project. Join thousands of Treehouse students and alumni in the community today. (Note: Only Treehouse students can comment or ask questions, but non-students are welcome to browse our conversations.)

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and a supportive community. Start your free trial today.

JavaScript

for loop exceeding max conditional?

I have an array of objects that store variables associated with each object.

I'm trying to loop through this array and perform a google maps direction service query on each object to wind up with a series of routes on a map.

The error I'm getting follows: "Uncaught TypeError: Cannot read property 'route' of undefined"

console.logging out the line in question reveals that my counter variable in the for loop is exceeding the limit of the length of the array. Makes sense why it returns undefined. I can't see why this counter should exceed the limit.

Code for the array and loop follows:

var allRoutes = [{
  name: "80x",
  path: path80x,
  route: route80x,
  poly: poly80x
},
{
  name: "71x",
  path: path71x,
  route: route71x,
  poly: poly71x
},
{
  name: "331",
  path: path331,
  route: route331,
  poly: poly331
},
{
  name: "43",
  path: path43,
  route: route43,
  poly: poly43
}];

for (var x=0;x<allRoutes.length;x++) {
  for (var i=1;i<allRoutes[x].path.length;i++) {
    DS.route({
      origin: allRoutes[x].path.getAt(i-1),
      destination: allRoutes[x].path.getAt(i),
      travelMode: google.maps.DirectionsTravelMode.DRIVING
    }, function(result, status) {
      if (status==google.maps.DirectionsStatus.OK) {
        for (var k=0, len=result.routes[0].overview_path.length;k<len;k++) {
          allRoutes[x].route.push(result.routes[0].overview_path[k]);
        }
      }
    });
  }
  allRoutes[x].poly.setPath(allRoutes[x].route);
}

So why is the counter variable 'x' looping through a fifth time?

2 Answers

Greg Kaleka
Greg Kaleka
39,018 Points

Are you sure it's looping a fifth time? I copied and pasted (and changed your object's properties to strings, since I don't have those variables sitting around), and added console.log("x = " + x);, and it looks to be working to me. I think something else is causing your issue.

I know it's looping five times because I'm console logging the error line to check what the value of x is when the error is produced. The value is showing 4.