To hide the navigation navbar with React Native, we set the screenOptions.headerShown option to false.
For instance, we write
<Stack.Navigator
screenOptions={{
headerShown: false,
}}
>
...
</Stack.Navigator>;
to set the headerShown option of the screenOptions prop object to false on the Stack.Navigator to hide the navbar.
To fix the React Native navigation paramlist never used error, we add '@typescript-eslint/parser' into .eslintrc.
For instance, in .eslintrc, we write
{
"parser": "@typescript-eslint/parser"
}
We also need to download ‘@typescript-eslint/parser’ in your dev dependencies
To do this, we run
npm i @typescript-eslint/parser --save-dev
To populate the right side of the navigation header with React Native, we set the screnOptions prop o
<Stack.Navigator>
<Stack.Group
screenOptions={({ route, navigation }) => ({
headerRight: () => <Button onPress={() => navigation.navigate("Home")} />,
})}
>
<Stack.Screen name="Home" component={HomeScreen} />
<Stack.Screen name="Profile" component={ProfileScreen} />
</Stack.Group>
<Stack.Group screenOptions={{ presentation: "modal" }}>
<Stack.Screen name="Settings" component={Settings} />
<Stack.Screen name="Share" component={Share} />
</Stack.Group>
</Stack.Navigator>;
to add the Stack.Group‘s screenOptions prop.
We set it to a function that has a button on the right by setting headerRight to a function that renders a Button.
To write unit tests in React, we can use the react-dom/test-utils package.
For instance, we write
import React from "react";
export default function Hello(props) {
if (props.name) {
return <h1>Hello, {props.name}!</h1>;
} else {
return <span>Hey, stranger</span>;
}
}
in hello.js.
Then in hello.test.js, we write
import React from "react";
import { render, unmountComponentAtNode } from "react-dom";
import { act } from "react-dom/test-utils";
import Hello from "./hello";
let container = null;
beforeEach(() => {
container = document.createElement("div");
document.body.appendChild(container);
});
afterEach(() => {
// cleanup on exiting
unmountComponentAtNode(container);
container.remove();
container = null;
});
it("renders with or without a name", () => {
act(() => {
render(<Hello />, container);
});
expect(container.textContent).toBe("Hey, stranger");
act(() => {
render(<Hello name="Jenny" />, container);
});
expect(container.textContent).toBe("Hello, Jenny!");
act(() => {
render(<Hello name="Margaret" />, container);
});
expect(container.textContent).toBe("Hello, Margaret!");
});
to add a test for the Hello component.
We mount the component with render
Then we check the rendered content with expect.
The beforeEach callback runs before each test.
We use
container = document.createElement("div");
to create the render target element.
And the afterEach callback runs after each test.
We clean up after our tests in the afterEach callback.
To remove top header from the navigation with React Native, we can set the static navigationOptions.header propety to null or callnavigation.setOptions.
For instance, we write
export default class Login extends Component {
static navigationOptions = {
header: null,
};
}
to set the navigationOptions.header property to null in our component to remove the header.
Also, we can write
setTimeout(() => {
navigation.setOptions({
header: () => (
<View style={{ backgroundColor: "white" }}>
<Text
style={[
{ color: "white" },
Platform.OS === "android" ? { fontSize: 20 } : { fontSize: 1 },
]}
>
.
</Text>
</View>
),
});
}, 1);
to call call navigation.setOptions with an object with the header property set to a white View to hide the header.