React navigation state management without redux

Question

I'm using React Navigation library for my React Native project and struggling to understand how to handle state with it. In normal React Native application I can have state at the top level component and pop events from child components via props, however with React Navigation it seems that I cannot pass any props to components used as Screens.

After reading through related GitHub issue it seems that library devs are very opinionated in forcing everyone to use some kind of global event handler - redux or mobx, I guess.

The handler which needs to modify the following state. I got stuck when I started to try to move the state inside the app as I couldn't figure out how to:

1. Pass the handler to the TaskForm component.
2. Pass the state as props to TaskList if its rendered as part of App.js

Please, avoid replying "just use redux". I believe that using redux in this example would be massive overkill.

Answer 1

I use react native and react navigation in my app without redux, and so far it’s working great. The trick is passing screenProps all the way down the line.

For example, I have a More view. I create a basic More view with 2 sub views in a stack:

class More extends Component {
    render() {
        return <something>
    }
}

class SubView1 extends Component {...}
class SubView2 extends Component {...}

Then I create the stack:

const MoreStack = StackNavigator({
More: {
    screen: More
}, 
SubView1: {
    screen: SubView1,
},
...
}, options);

And then I create a wrapper class that I export:

export default class MoreExport extends Component {
    static navigationOptions = {
        title: "More"
    }

    render() {
        return <MoreStack screenProps={this.props.screenProps} />;
    }
}

If all of this is in More.js, I can just import More from More.js and use it anywhere else.

If I then pass in screenProps to my root view and then have a wrapper class for each layer, I can pass the screenProps all the way down, and all views can access them using this.props.screenProps.

I use a wrapper like the one above around each StackNavigator and TabNavigator, and the screenProps are passed all the way down.

For example, in my root class’s render method, I could do:

return <More screenProps={{prop1: something, prop2: somethingElse}} />

And then the More class and each SubView in the MoreStack would all have access to these props.

Feel free to let me know if you want more clarification!

Disclaimer: I don’t know if this is the correct or recommended way to do it, but it does work

Answer 2

You can set param to navigation like this:

static navigationOptions = ({ navigation }) => {
    return {
        tabBarIcon: ({ tintColor, focused }) =>
            <View>
                <Icon name="bell-ring" size={24} color={focused ? 'green' : 'black'} />
                {(navigation.state.params.badgeCount && navigation.state.params.badgeCount > 0) ?
                    <Text>{navigation.state.params.badgeCount}</Text>
                    :
                    <View></View>
                }
            </View>
    }
}

and change badgeCount by:

this.props.navigation.setParams({ badgeCount: 3 })

Answer 3

After being inspired by steffeydev I looked more around react community issues and found a very simple example of wrapper using function.

It's surprisingly simple solution and I don't know why I didn't think about it before. The function is the following: const createComponent = (instance, props) => navProps => React.createElement(instance, Object.assign({}, props, navProps));

Thanks for inspiration and pointing me to screenProps which lead me to finding this solution.

Answer 4

I was struggling with the same issue and tried some of the other answers before discovering the following part of the documentation for React Navigation: https://reactnavigation.org/docs/en/stack-navigator.html#params.

Essentially, each Screen in the Stack can be passed params which can include handlers and then the various screens can interact with the application state.

My general structure is then to have an App class with state and handlers and the handlers are then passed into each Navigation Screen as needed. I'm not sure if I have this pattern right, but it's the way I understood the general React tutorial.

Example: In my demo app, I have a page flow like this:

• Park finder screen -> Park detail screen (with Bookmark action)
• Bookmark list screen -> Park detail screen

If you find a park, you can click on a Bookmark button which adds the park to the list of bookmarks shown on the Bookmark screen. You can then click on a park bookmark to see the details.

My App looks generally like this:

import React, { Component } from 'react';

// Screens
import ParkFinderScreen from './Components/ParkFinderScreen';
import ParkBookmarksScreen from './Components/ParkBookmarksScreen';
import ParkDetailsScreen from './Components/ParkDetailsScreen';

// Navigation
import { createStackNavigator, createBottomTabNavigator, createAppContainer } from 'react-navigation';

class App extends Component {
  constructor(props) {
    super(props);

    this.state = {
      bookmarks: new Map()
    };
  }

  // Bookmark the park shown in the detail section.
  handleBookmark (park) {
    let newBookmarks = this.state.bookmarks;

    newBookmarks.set(park.parkCode, park);

    this.setState({
      bookmarks: newBookmarks
    });
  }

  render() {
    const FinderStack = createStackNavigator(
      {
        ParkFinder: {
          screen: ParkFinderScreen
        },
        ParkFinderDetails: {
          screen: ParkDetailsScreen,
          params: {
            handleBookmark: (park) => this.handleBookmark(park),
          }
        },
      }
    );

    const BookmarksStack = createStackNavigator(
      {
        ParkBookmarks: {
          screen: ParkBookmarksScreen,
          params: {
            bookmarks: this.state.bookmarks
          }
        },
        ParkBookmarksDetails: {
          screen: ParkDetailsScreen,
        },
      }
    );

    const AppNavigator = createBottomTabNavigator(
      {
        Bookmarks: BookmarksStack,
        Finder: FinderStack,
      }
    );

    const AppContainer = createAppContainer(AppNavigator);

    return (
      <AppContainer/>
    );
  }
}

export default App;

I'm using Apollo Client, but I've removed those parts.

In the Screen components, you can access the props like other ones using this.props.navigation.getParam('bookmarks').

One issue I encountered was that whenever I change the App state, I'm taken to the first screen. The state is updated, but it's a little disorienting. I'm not sure if there is a way to update the App state while staying on the screen. I can sort of understand that given the App state has updated, all the children need to be updated and so the current screen (which is part of a child I think) is reset. I don't know if that is a limitation of the system or a byproduct of how I designed the components.

I hope this helps someone. This seems to keep with the intended behavior of React Native. The library team really seems to want you to not use Redux. https://reactnavigation.org/docs/en/redux-integration.html