Add a first query filter

[Freyja-moth]

What problem does this solve or what need does it fill?

There's no way to currently get the first entity that matches a given query from a SystemParameter.

What solution would you like?

Something like this

fn destroy_first(wall: First<Entity, With<Wall>>, mut commands: Commands) {
    let entity = wall.into_inner();

    commands.entity(entity).despawn();
} 

What alternative(s) have you considered?

Just using a query and taking the first from the iterator.

[LikeLakers2]

If I may ask, why is the alternative that you listed ("Just using a query and taking the first from the iterator.") insufficient for your needs?

[Freyja-moth]

It's not really, at most it's two lines of code, but that was also the case with Single.

I mostly just thought it'd be a nice thing to have.

[LikeLakers2]

Okay, that's fair. The way your issue was worded, I thought the alternative had some deficiency that made it undesirable for your use case.

Thank you for clarifying.

[alice-i-cecile]

I prefer the .iter().first() style here, and don't think this is worth the API space.