defeffect

Add effects:

defeffect effect-a (a b) (action el at-place?)
  case-default action
    do
    :mount (println "|mounted")
    :before-update (println "|before update")
    :update (println "|updated")
    :unmount (println "|will unmount")

defcomp comp-a (x y z)
  []
    effect-a a b
    div {}
      <> "|DEMO"
  • [] a b are arguments. they can also be old arguments during unmounting,
  • action can be :mount :before-update :update or :unmount,
  • el refers to root element of component.
  • at-place? being true if change happen exactly from this component, rather than from parents.

Notice that to add effects into component, we need to use a vector. So it's also possible to add multiple effects here:

[]
  defeffect-a a b
  defeffect-b c d
  div $ {}

Respo is different from React. You can not dispatch action during rendering, or inside effects. So there will be no access to dispatch!, and should not have actions.