React OCaml API

myComponent.ml

open ReactDOM

module MyComponent = struct
  (* Component Properties *)
  type props = {count: int}

  (* Hey, state can be any type! *)
  type state = string

  (* Initializer *)
  let getInitialState props = "neverBeenClicked"

  (* Signal handlers - these simply return the next state. *)
  let componentWillReceiveProps props (prevProps, prevState) = prevState
  let handleClick {props; state; updater} evt = "hasBeenClicked"

  (* Render: props and state as arguments, just like we've always wanted *)
  let render {props; state; updater} = [
    Div.make
      ~styleString: "Omit to rely on defaults #thanksOCaml - no really, thanks OCaml"
      ~className: ("P:" ^ props.prefix ^ " S:" ^ state)
      ~onClick: (updater handleClick)
      ~children: []
  ]
  
end

(* CreateComponent as a Functor. OCaml's (SML's) module system proves to be very powerful *)
module MyComponentClass = React.CreateComponent (MyComponent)

What's the purpose of updater, I mean what does it do ?

Sorry for the late reply - I suspect @IwanKaramazow knows what updater is for now - now that he actually implemented it.