side-menu-reducer

side.re

reducer: (action, state) =>
  switch (action) {
  | Open =>
    ReasonReact.UpdateWithSideEffects(
      {...state, isVisible: true},
      (
        self => {
          Animated.Value.setValue(
            self.state.animation,
            self.state.direction == Right ? menuWidth : -. menuWidth,
          );
          Animated.start(
            Animated.spring(
              ~value=self.state.animation,
              ~toValue=`raw(0.),
              ~friction=10.,
              ~tension=35.,
              (),
            ),
            (),
          );
        }
      ),
    )
  | Close =>
    ReasonReact.SideEffects(
      (
        self => {
          Animated.Value.setValue(self.state.animation, 0.);
          Animated.start(
            Animated.spring(
              ~value=self.state.animation,
              ~toValue=
                `raw(
                  /** add with 45pt to ensure that the menu will disappear completely */
                  self.state.direction
                  == Right ?
                    menuWidth +. 45. : -. (menuWidth +. 45.),
                ),
              ~friction=10.,
              ~tension=50.,
              (),
            ),
            ~callback=_evt => self.send(Set(false)),
            (),
          );
          ();
        }
      ),
    )
  | ChangeVisibility(isVisible) =>
    ReasonReact.SideEffects((self => self.send(isVisible ? Open : Close)))
  | Set(isVisible) => ReasonReact.Update({...state, isVisible})
}