This page covers Tutorial v2. Elm 0.18.
The plan for changing a player's level is as follows:
(1) When the user clicks the increase or decrease button we trigger a message
ChangeLevel with the
howMuch as payload.
(2) Html.program (which Navigation wraps) will send this message back to
Update will return a command to save the player.
(4) The Elm runtime executes the command (trigger an API call) and we will get a result back, which is either a successful save or a failure. In the success case we trigger a
OnPlayerSave message with the updated player as payload.
Update we update the
players model and return it.
(6) Then Html.program will render the application with the updated model.