prva verzija

src/App.js

@@ -0,0 +1,45 @@
+// ./src/App.js
+
+import React, { Component } from 'react'
+import UsernameForm from './UsernameForm'
+import Chat from './Chat'
+
+class App extends Component {
+  state = {
+    currentUsername: null,
+    currentId: null,
+    currentScreen: 'usernameForm'
+  }
+
+  onUsernameSubmitted = username => {
+    fetch('http://localhost:3001/users', {
+      method: 'POST',
+      headers: {
+        'Content-Type': 'application/json'
+      },
+      body: JSON.stringify({ username })
+    })
+      .then(response => response.json())
+      .then(data => {
+        this.setState({
+          currentId: data.id,
+          currentUsername: data.name,
+          currentScreen: 'chat'
+        })
+      })
+      .catch(error => {
+        console.error('error', error)
+      })
+  }
+
+  render() {
+    if (this.state.currentScreen === 'usernameForm') {
+      return <UsernameForm handleSubmit={this.onUsernameSubmitted} />
+    }
+    
+    if (this.state.currentScreen === 'chat') {
+      return <Chat currentId={this.state.currentId} />
+    }
+  }
+}
+export default App;