This page covers Tutorial v2. Elm 0.18.

Messages

Let's start by adding the messages we will need.

In src/Msgs.elm add:

import Http
...

type Msg
    ...
    | ChangeLevel Player Int
    | OnPlayerSave (Result Http.Error Player)

• ChangeLevel will trigger when the user wants to change the level. The second parameter is an integer that indicates how much to change the level e.g. -1 to decrease or 1 to increase.
• Then we will send a request to update the player to the API. OnPlayerSave will be triggered after the response from the API is received.
• OnPlayerSave will either carry the updated player on success or the Http error on failure.