Add the addListener binding. (rescript-react-native#9)

Author: Natim

example/src/components/Search.re

@@ -24,7 +24,10 @@ module SearchHeader = {
 
 module SearchList = {
  [@react.component]
- let make = (~navigation) => placeholder(~navigation, ~text="SearchList");
+ let make = (~navigation) => {
+ navigation.addListener(`didFocus, event => Js.log2("didFocus", event));
+ placeholder(~navigation, ~text="SearchList");
+ };
 
  NavigationOptions.(
  make->setDynamicNavigationOptions(params =>

src/Navigation.re

@@ -1,5 +1,15 @@
+open ReactNative;
 type t;
 
+type navigationEventPayload = {
+ .
+ "action": NavigationActions.action,
+ "context": string,
+ "type": string,
+ "state": NavigationState.t,
+ "lastState": Js.Nullable.t(NavigationState.t),
+};
+
 [@bs.val] [@bs.module "react-navigation"]
 external navigationContext: React.Context.t(t) = "NavigationContext";
 
@@ -14,7 +24,17 @@ external navigateWithParams: (t, string, Js.t({..})) => unit = "navigate";
 [@bs.send] external goBackToRoute: (t, string) => unit = "";
 [@bs.send] external getParam: (t, string) => Js.nullable('a) = "";
 [@bs.send] external getParamWithDefault: (t, string, 'a) => 'a = "getParam";
-// TODO: addListener, setParams, ...
+[@bs.send]
+external addListener:
+ (
+ t,
+ [@bs.string] [ | `didBlur | `didFocus | `willBlur | `willFocus],
+ navigationEventPayload => unit
+ ) =>
+ EventSubscription.t =
+ "addListener";
+
+// TODO: setParams, ...
 // Stack Actions
 // TODO: push, replace, ...
 [@bs.send] external pop: t => unit = "";