Conditional updates

[SorenHolstHansen]

Does leptos support conditional updates of signals for instance if the update function returns an Err. I know that you can wrap the signal in a Result, but that doesn't work for my use case

I was thinking something along the lines of this (the example is thought up, but my use case is also game history related, where I can't use a Result<GameHistory> which would lose the data if it was an Err)

#[component]
fn MyComponent() -> impl IntoView {
  let game_history = RwSignal::new(GameHistory::new());

  view! {
    <button on:click=move |_| {
      game_history.update(|history| {
        if let Err(e) = history.purchase_artifact() {
          // if this is an Err, say the player doesn't have enough money, then don't update the game_history signal
          show_error(e);
        }
      });
    }>
      "Update history"
    </button>
  }
}

[gbj]

This depends on the signature of purchase_artifact. If it takes &self then you can do a conditional update with something like:

match game_history.with(GameHistory::purchase_artifact) {
  Err(e) => show_error(e),
  Ok(value) => game_history.update(/* ... */)
}

If it takes &mut, then there is not a way to do this without the framework adding some additional PartialEq constraint or something, or creating a special helper method that doesn't currently exist.

[SorenHolstHansen]

Cool, thanks! Think I will just do the update anyways for now