how to fix: Cannot infer topic type for topic turtle1/teleport_absolute as it is not yet advertised ROS

Question

I am trying to send a Teleport absolute message to a turtle with roslibjs. This is my code

function publish() {
  connect()
  const cmdVel = new ROSLIB.Topic({
    ros: ros,
    name: "turtle1/teleport_absolute",
    messageType: "turtle1/teleport_absolute"
  });
    
  const data = new ROSLIB.Message({
    x : linear.x,
    y : linear.y,
    theta : 8
  });
  // publishes to the queue
  cmdVel.publish(data);
}

but whenever I run the Publish function I get this error

 publish: Cannot infer topic type for topic /tf2_web_republisher/goal as it is not yet advertised

I tried sending basic twist messages before this and they worked, they looked like this.

var cmdVel = new ROSLIB.Topic({
  ros : ros,
  name : '/cmd_vel',
  messageType : 'geometry_msgs/Twist'
 });
    
 var twist = new ROSLIB.Message({
   linear : {
     x : 0.1,
     y : 0.2,
     z : 0.3
   },
   angular : {
     x : -0.1,
     y : -0.2,
     z : -0.3
   }
});

have tried running

    function publish() {
        connect()
        const cmdVel = new ROSLIB.Topic({
            ros: ros,
            name: "turtle1/teleport_absolute",
            messageType: "turtle1/teleport_absolute"
        });

        const data = new ROSLIB.Message({
            x : linear.x,
            y : linear.y,
            theta : 8
            });
        // publishes to the queue
        cmdVel.publish(data);
    }

doesn't work

There is also very little good documentation on this subject so finding answers for things such as this is a problem.

Answer 1

When using the roslibjs you need to pass both the topic name and the message type. And you had a typo where you set both the topic name and message type as the same.

It should be

const cmdVel = new ROSLIB.Topic({
    ros: ros,
    name: "turtle1/teleport_absolute",
    messageType: "geometry_msgs/Twist"
});