Add mutliple contexts example

examples/context/multiple-contexts.js

@@ -0,0 +1,36 @@
+// Create a theme context, defaulting to light theme
+// highlight-next-line
+const ThemeContext = React.createContext('light');
+
+// Signed-in user context
+const UserContext = React.createContext();
+
+class App extends React.Component {
+  static propTypes = {
+    theme: PropTypes.string,
+    signedInUser: PropTypes.shape({
+      id: number,
+      name: string,
+      avatar: string,
+    }),
+  };
+
+  render() {
+    return (
+      <ThemeContext.Provider value={this.props.theme}>
+        <UserContext.Provider
+          value={this.props.signedInUser}>
+          <ThemeContext.Consumer>
+            {theme => (
+              <UserContext.Consumer>
+                {user => (
+                  <ProfilePage user={user} theme={theme} />
+                )}
+              </UserContext.Consumer>
+            )}
+          </ThemeContext.Consumer>
+        </UserContext.Provider>
+      </ThemeContext.Provider>
+    );
+  }
+}