From c5f444936bc72c60bf42ab466cb0e5b1f8f7f30a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Cichoci=C5=84ski?= <tomaszcichocinski@gmail.com>
Date: Thu, 6 Sep 2018 21:45:56 +0200
Subject: [PATCH] Changes StackNavigator.Screen from stateless to
 statelessWithRetainedProps

It allow us to check for header props changes and call navigation.setOptions when props changes. Should fix #122. Only problem are properties that are recreated every time like Style.t or (probably) Header.returnsComponent.
---
 example/Admin.re       | 31 ++++++++++++++++++++-----
 src/StackNavigator.re  | 52 +++++++++++++++++++++++++++++++++++++++---
 src/StackNavigator.rei | 13 +++++++++--
 3 files changed, 85 insertions(+), 11 deletions(-)

diff --git a/example/Admin.re b/example/Admin.re
index 82c162a..f767c02 100644
--- a/example/Admin.re
+++ b/example/Admin.re
@@ -1,6 +1,11 @@
 open Rebolt;
 
-let component = ReasonReact.statelessComponent("Admin");
+type action =
+  | Increment;
+
+type state = {counter: int};
+
+let component = ReasonReact.reducerComponent("Admin");
 
 module Styles = {
   open Style;
@@ -15,13 +20,15 @@ module Styles = {
       marginTop(Pt(16.)),
       backgroundColor(String(color)),
       borderRadius(20.),
-      width(Pt(100.)),
+      width(Pt(120.)),
     ]);
   let buttonText = style([textAlign(Center)]);
   let title = style([fontSize(Float(20.))]);
 };
 
-let renderButtons = (nav: NavigationConfig.StackNavigator.navigation) =>
+let getHeaderTitle = counter => "Admin" ++ string_of_int(counter);
+
+let renderButtons = (nav: NavigationConfig.StackNavigator.navigation, send) =>
   <View>
     <TouchableOpacity
       style=(Styles.button("#4cd964"))
@@ -32,13 +39,25 @@ let renderButtons = (nav: NavigationConfig.StackNavigator.navigation) =>
       style=(Styles.button("#ff9500")) onPress=(_e => nav.pop())>
       <Text style=Styles.buttonText> (ReasonReact.string("Pop")) </Text>
     </TouchableOpacity>
+    <TouchableOpacity
+      style=(Styles.button("rgb(63,97,165)"))
+      onPress=(_e => send(Increment))>
+      <Text style=Styles.buttonText>
+        (ReasonReact.string("Change header title"))
+      </Text>
+    </TouchableOpacity>
   </View>;
 
 let make = (~navigation, _children) => {
   ...component,
-  render: _self =>
+  initialState: () => {counter: 0},
+  reducer: (action, state) =>
+    switch (action) {
+    | Increment => ReasonReact.Update({counter: state.counter + 1})
+    },
+  render: self =>
     <NavigationConfig.StackNavigator.Screen
-      headerTitle="Admindkasldkasldkdasdas"
+      headerTitle=(getHeaderTitle(self.state.counter))
       navigation
       headerStyle=Style.(style([backgroundColor(String("#FFF"))]))>
       ...(
@@ -47,7 +66,7 @@ let make = (~navigation, _children) => {
                <Text style=Styles.title>
                  (ReasonReact.string("Admin screen"))
                </Text>
-               (renderButtons(navigation))
+               (renderButtons(navigation, self.send))
              </View>
          )
     </NavigationConfig.StackNavigator.Screen>,
diff --git a/src/StackNavigator.re b/src/StackNavigator.re
index c19218e..676261a 100644
--- a/src/StackNavigator.re
+++ b/src/StackNavigator.re
@@ -541,8 +541,19 @@ module CreateStackNavigator = (Config: {type route;}) => {
       },
     };
     module Screen = {
+      type retainedProps = {
+        style: option(Style.t),
+        headerTitle: option(string),
+        /* headerStyle: option(Style.t), */
+        headerLeft: option(Header.returnsComponent),
+        headerCenter: option(Header.returnsComponent),
+        headerRight: option(Header.returnsComponent),
+        animation: option(Animation.t),
+      };
+
       let flexOne = Style.(style([flex(1.)]));
-      let component = ReasonReact.statelessComponent("CallstackScreen");
+      let component =
+        ReasonReact.statelessComponentWithRetainedProps("CallstackScreen");
       let make =
           (
             ~navigation: navigation,
@@ -556,7 +567,16 @@ module CreateStackNavigator = (Config: {type route;}) => {
             children,
           ) => {
         ...component,
-        didMount: _self => {
+        retainedProps: {
+          style,
+          headerTitle,
+          /* headerStyle, */
+          headerLeft,
+          headerCenter,
+          headerRight,
+          animation,
+        },
+        didMount: _self =>
           navigation.setOptions({
             header: {
               title: headerTitle,
@@ -567,7 +587,33 @@ module CreateStackNavigator = (Config: {type route;}) => {
             },
             animation,
             style,
-          });
+          }),
+        didUpdate: ({oldSelf: {retainedProps}}) => {
+          let propsChanged =
+            [
+              retainedProps.style !== style,
+              retainedProps.headerTitle !== headerTitle,
+              /* oldSelf.retainedProps.headerStyle !== headerStyle, */
+              retainedProps.headerLeft !== headerLeft,
+              retainedProps.headerCenter !== headerCenter,
+              retainedProps.headerRight !== headerRight,
+              retainedProps.animation !== animation,
+            ]
+            |> Belt.List.some(_, a => a);
+
+          if (propsChanged) {
+            navigation.setOptions({
+              header: {
+                title: headerTitle,
+                style: headerStyle,
+                center: headerCenter,
+                left: headerLeft,
+                right: headerRight,
+              },
+              animation,
+              style,
+            });
+          };
           ();
         },
         render: _self => {
diff --git a/src/StackNavigator.rei b/src/StackNavigator.rei
index 4afa6c3..282098f 100644
--- a/src/StackNavigator.rei
+++ b/src/StackNavigator.rei
@@ -40,6 +40,15 @@ module CreateStackNavigator:
         );
       module Animation = Animation;
       module Screen: {
+        type retainedProps = {
+          style: option(Rebolt.Style.t),
+          headerTitle: option(string),
+          /* headerStyle: option(Rebolt.Style.t), */
+          headerLeft: option(Header.returnsComponent),
+          headerCenter: option(Header.returnsComponent),
+          headerRight: option(Header.returnsComponent),
+          animation: option(Animation.t),
+        };
         let make:
           (
             ~navigation: navigation,
@@ -55,8 +64,8 @@ module CreateStackNavigator:
           ReasonReact.componentSpec(
             ReasonReact.stateless,
             ReasonReact.stateless,
-            ReasonReact.noRetainedProps,
-            ReasonReact.noRetainedProps,
+            retainedProps,
+            retainedProps,
             ReasonReact.actionless,
           );
       };