Description
According to the comment for CommandResult class:
/// Combined execution state of a `Command` represented using four of its fields.
/// A [CommandResult] will be issued for any state change of any of its fields
/// During normal command execution you will get this items by listening at the command's [.results] ValueListenable.
/// 1. If the command was just newly created you will get `param data, null, null, false` (paramData, data, error, isExecuting)
/// 2. When calling execute: `param data, null, null, true`
/// 3. When execution finishes: `param data, the result, null, false`
/// `param data` is the data that you pass as parameter when calling the command
In short, the way to tell whether a command has yet to execute or has completed execution is to see if result.data is null.
However, the actual implementation is inconsistent. The result.data always returns the initial value set on command creation before executing. If the command returns the same value after execution, there is no way to tell them apart. Ideally, CommandResult should have both a getter that returns the initial value before the actual data, as well as a getter that follows the comment to indicate a newly created command before execution.
Moreover, even when CommandResult were fixed to follow its comments, for commands that have no return value, there is still no way to tell if execution has yet started, as the result.data will always be null before and after the execution.
I know I can use another field to track that info, but it's not an elegant solution. The Command class should embed that state internally, just like in FutureBuilder you can use snapshot.connectionState to differentiate ConnectionState.none against ConnectionState.done.