API DOCS for: on-watch.public.ts

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onWatch

Reruns the watchFn when the observed inputs change.

Use onWatch to observe changes on a set of inputs, and then re-execute the watchFn when those inputs change.

The watchFn only executes if the observed inputs change. To observe the inputs use the obs function to wrap property reads. This creates subscriptions which will trigger the watchFn to re-run.

See: Observer

@public

Example

The onWatch function is used to observe the state.count property. Any changes to the state.count cause the watchFn to execute which in turn updates the state.doubleCount to the double of state.count.

@param watch - Function which should be re-executed when changes to the inputs are detected
@public

Observer

Used to signal to Qwik which state should be watched for changes.

The Observer is passed into the watchFn of onWatch. It is intended to be used to wrap state objects in a read proxy which signals to Qwik which properties should be watched for changes. A change to any of the properties cause the watchFn to re-run.

Example

The obs passed into the watchFn is used to mark state.count as a property of interest. Any changes to the state.count property will cause the watchFn to re-run.

See: onWatch

@public