So called working

App.tsx

@@ -5,6 +5,17 @@ import { PostsContainer } from "./src/components/PostsContainer";
 import { NavigationContainer } from "@react-navigation/native";
 import { createNativeStackNavigator } from "@react-navigation/native-stack";
 import { NewPostContainer } from "./src/components/NewPostContainer";
+import { NativeStackNavigationProp } from "@react-navigation/native-stack";
+
+type RootStackParamList = {
+  Home: undefined;
+  New: undefined;
+};
+
+export type HomeScreenNavigationProp = NativeStackNavigationProp<
+  RootStackParamList,
+  "Home"
+  >;
 
 const Stack = createNativeStackNavigator();
 

src/components/NewPostContainer.tsx

@@ -1,7 +1,7 @@
 import React from "react";
 import { View, Text, TextInput, Button } from "react-native";
 import { style } from "../util/style";
-import { createPost, NewPost } from "../util/api";
+import { createPost, NewPost, submitLogin } from "../util/api";
 
 export function NewPostContainer({ navigation }): JSX.Element {
   const [currentInput, setCurrentInput] = React.useState<string>("");
@@ -21,13 +21,20 @@ export function NewPostContainer({ navigation }): JSX.Element {
       <Button
         title="Post"
         onPress={() => {
-          if (currentInput.length > 0) {
+          async function submit(): Promise<void> {
+            const user = (await submitLogin("demouser", "demopw")) ?? {
+              token: "",
+            };
             const p: NewPost = {
               content: currentInput,
-              token: "token",
+              token: user.token,
             };
-            createPost(p);
+            await createPost(p);
             setCurrentInput("");
+          }
+          if (currentInput.length > 0) {
+            submit();
+            navigation.navigate("Home");
           } else {
             setCurrentInputError("Post must not be empty!");
           }