Rule proposal: prefer-empty #2350

reduckted · 2025-04-03T11:13:54Z

reduckted
Apr 3, 2025

Using the @empty flow control block is more readable than using an @if block to achieve the same thing.

@if (items.length > 0) {
    for (item of items; track $index) {
        {{ item }}
    }
} @else {
    There are no items
}

vs

for (item of items; track $index) {
    {{ item }}
} @empty {
    There are no items
}

There are two cases that I think can be detected.

An @if with only an @for within it, and an @else that checks the length of the same collection used in the @for block.
An @for block, followed immediately by an @if block that checks the length of the same collection used in the @for block.

I'm not sold on the name though. It could easily be interpreted as something that is the opposite of no-empty-control-flow. Other possible names:

rubiesonthesky · 2025-04-09T19:47:10Z

I think prefer-empty is too general. prefer-for-empty would indicate that it's related to for. I think prefer-empty-block is also better than just prefer-empty. https://angular.dev/guide/templates/control-flow#providing-a-fallback-for-for-blocks-with-the-empty-block has heading Talks about "fallback", so the name could also use that?

0 replies

reduckted · 2025-05-11T10:32:35Z

Implemented in #2352.

0 replies