See When Action Completes

[caelinsutch]

I can't figure out how to implement a callback on an ActionClient when the action completes, just on updates and when the action is successfully received. As mentioned in line 190 here:

  /**
   * Send a goal and asynchronously get the result.
   *
   * The result of the returned Promise is set to a ClientGoalHandle when receipt of the goal
   * is acknowledged by an action server.
   *
   * @param {object} goal - The goal request.
   * @param {function} feedbackCallback - Callback function for feedback associated with the goal.
   * @param {object} goalUuid - Universally unique identifier for the goal. If None, then a random UUID is generated.
   * @returns {Promise} - A Promise to a goal handle that resolves when the goal request has been accepted or rejected.
   */

However, on line 313, I see the function _getResult:

  /**
   * Request the result for an active goal asynchronously.
   * @ignore
   * @param {ClientGoalHandle} goalHandle - Handle to the goal to cancel.
   * @returns {Promise} - A Promise that resolves when the get result request has been processed.
   */

Is this something that should be implemented, or an accepted restriction?

[mattrichard]

The comments do appear somewhat misleading. The sendGoal function returns a Promise which resolves to a goal handle. To get the final result (i.e. the completion) you need to call getResult() on the goal handle and wait for that Promise to resolve. You can see this in the examples here

https://github.com/RobotWebTools/rclnodejs/blob/db7721ec3042b355d45089cb77aec9c34c6577b8/example/action-client-example.js#L52

That promise will resolve when the action completes, and it will contain the final result and status. Let me know if you need more info.

[minggangw]

Shall we update the comments accordingly to make it clear?

[caelinsutch]

I think the docs should be updated for sure.