A pure function that, when applied to an Observable, returns an Observable.
A pure function that, when applied to an Observable, returns an Observable.
An dependency array with fixed length. When one of the dependencies
changes the Observable in init
will emit an array of all the dependencies.
Accepts a function that returns an Observable. Optionally accepts an array of dependencies which will be turned into Observable and be passed to the
init
function.React functional components are called many times during their lifecycle. Create or transform Observables in
init
function so that the operations won't be repeatedly performed.⚠ Note:
useObservable
will callinit
once and always return the same Observable. It is not safe to access closure (except other Observables) directly insideinit
. You should use ref or pass them as dependencies through the second argument.⚠ Note: Due to rules of hooks you can either offer or omit the dependencies array but do not change to one another during Component's life cycle. The length of the dependencies array must also be fixed.