Timing of effects

Although useEffect is deferred until after the browser has painted, it's guaranteed to fire before any new renders. React will always flush a previous render's effects before starting a new update.

Is this true in both concurrent and non-concurrent mode. It would appear intuitively that these two call-sites in non-concurrent mode would be deterministic:

ReactDOM.render(<Foo>, container)
ReactDOM.render(<Foo>, container)

That is it would invoke a new render before the effect in the first render has been invoked.

If so would it make more sense to specify it is only in relation to effects i.e previous effects are guaranteed to run before future effects.

As it stands, it looks appears as though the "render" call-site is non-deterministic in non-concurrent.

Comienza revisando la afirmación citada de la documentación sobre que los efectos se vacían antes de nuevos renders y, después, compara su redacción con los dos puntos de llamada de ReactDOM.render y con el comportamiento tanto concurrent como non-concurrent. Se considera terminado cuando la documentación indique claramente la garantía admitida y resuelva si se aplica a los renders en general o únicamente al orden de los efectos.