useIsDefined

v0.0.15testeddemo

Reactive counterpart to {@link isDefined}. Returns a `ComputedRef<boolean>` that re-evaluates whenever the source ref, getter, or plain value resolves to a non-nullish value. Use this when the definedness itself needs to drive reactivity (templates, watchers, derived state); reach for the synchronous {@link isDefined} when you only need a one-off type guard.

Source Tests

Examples

const data = ref<Data | null>(null);
const ready = useIsDefined(data);
watch(ready, isReady => isReady && render());

const hasResult = useIsDefined(() => store.result);

Demo

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Signature

export function useIsDefined<T>(value: MaybeRefOrGetter<T>): UseIsDefinedReturn{ ... }

Type Parameters

T

Parameters

Parameter	Type	Default	Description
`value`	`MaybeRefOrGetter<T>`	—	The reactive source (ref, getter, or value)

Returns

UseIsDefinedReturnA computed boolean, `true` while the source is non-nullish