Add ActionCable to rescript (#565) (#570)

* add ActionCable to rescript (#565)

* unsubscribe from action cable when component didunmount

* format rescript

client/app/bundles/comments/rescript/ReScriptShow.res

@@ -15,6 +15,10 @@ let reducer = (_, action: action): state => {
   }
 }
 
+type subscriptionStatus =
+  | Disconnected(ActionCable.subscription<unit>)
+  | Connected(ActionCable.subscription<unit>)
+
 @react.component
 let default = () => {
   let (state, dispatch) = React.useReducer(
@@ -32,6 +36,33 @@ let default = () => {
     }
   }
 
+  let subscribeToCommentsChannel = () => {
+    ActionCable.subscribeConsumer(
+      "CommentsChannel",
+      {
+        connected: () => {
+          Js.Console.log("Connected")
+        },
+        received: (data: Actions.Fetch.t) => {
+          SetComments([data])->dispatch
+        },
+        disconnected: () => {
+          Js.Console.log("Disconnected")
+        },
+      },
+    )
+  }
+
+  React.useEffect1(_ => {
+    let scription = subscribeToCommentsChannel()
+
+    Some(
+      () => {
+        ActionCable.unsubscribeSubscription(scription)
+      },
+    )
+  }, [])
+
   React.useEffect1(_ => {
     fetchData()->ignore
     None

client/app/bundles/comments/rescript/bindings/ActionCable.res

@@ -0,0 +1,39 @@
+type webSocket
+type optionalWebSocket = option<webSocket>
+type subscriptions
+type consumer = {
+  disconnect: unit => unit,
+  subscriptions: subscriptions,
+}
+type actionCable = {createConsumer: unit => consumer}
+type createConsumer
+type subscription<'sendData> = {
+  consumer: consumer,
+  send: 'sendData => unit,
+}
+type subscriprtionCallbacks<'updateData> = {
+  connected: unit => unit,
+  received: 'updateData => unit,
+  disconnected: unit => unit,
+}
+
+@val @scope("window") @return(nullable)
+external webSocket: option<webSocket> = "WebSocket"
+@val external actionCable: actionCable = "ActionCable"
+@send
+external createSubscription: (
+  subscriptions,
+  string,
+  subscriprtionCallbacks<'updateData>,
+) => subscription<'sendData'> = "create"
+@send external sendData: (subscription<'sendData>, 'sendData) => unit = "send"
+@send external unsubscribeSubscription: subscription<'sendData'> => unit = "unsubscribe"
+@send external diconnectConsumer: consumer => unit = "disconnect"
+
+let subscribeConsumer = (
+  channnelName: string,
+  subscriprtionCallbacks: subscriprtionCallbacks<'updateData>,
+) => {
+  let consumer = actionCable.createConsumer()
+  createSubscription(consumer.subscriptions, channnelName, subscriprtionCallbacks)
+}