`class type resizeObserverSize = object ... end`
`class type resizeObserverEntry = object ... end`
`class type resizeObserverOptions = object ... end`
`class type resizeObserver = object ... end`
`val empty_resize_observer_options : unit -> resizeObserverOptions Js.t`
`val resizeObserver : ((resizeObserverEntry Js.t Js.js_array Js.t -> resizeObserver Js.t -> unit) Js.callback -> resizeObserver Js.t) Js.constr`
`val is_supported : unit -> bool`
`val observe : node:Dom.node Js.t -> f:(resizeObserverEntry Js.t Js.js_array Js.t -> resizeObserver Js.t -> unit) -> ?box:Js.js_string Js.t -> unit -> resizeObserver Js.t`

Helper to create a new observer and connect it to a node.