react render empty

according to react doc

Booleans, Null, and Undefined Are Ignored

falsenullundefined, and true are valid children. They simply don’t render. These JSX expressions will all render to the same thing:

https://reactjs.org/docs/jsx-in-depth.html#booleans-null-and-undefined-are-ignored

so



class x extends Component{
     render(){
       return(null);
    }
}


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good summary for react redux thunk

source:
https://medium.com/@stowball/a-dummys-guide-to-redux-and-thunk-in-react-d8904a7005d3

  1. There is 1 global state object that manages the state for your entire application. In this example, it will behave identically to our initial component’s state. It is the single source of truth.
  2. The only way to modify the state is through emitting an action, which is an object that describes what should change. Action Creators are the functions that are dispatched to emit a change – all they do is return an action.
  3. When an action is dispatched, a Reducer is the function that actually changes the state appropriate to that action – or returns the existing state if the action is not applicable to that reducer.
  4. Reducers are “pure functions”. They should not have any side-effects nor mutate the state — they must return a modified copy.
  5. Individual reducers are combined into a single rootReducer to create the discrete properties of the state.
  6. The Store is the thing that brings it all together: it represents the state by using the rootReducer, any middleware (Thunk in our case), and allows you to actually dispatch actions.
  7. For using Redux in React, the <Provider /> component wraps the entire application and passes the storedown to all children.

https://codeburst.io/redux-a-crud-example-abb834d763c9

Android React native app

Have played around react native, and published an android app earlier.

some thoughts:

  1. navigator

    this would normally be the entry point, which define the landing page, and how routing to different pages works.


<Navigator
    initialRoute={{ title: 'Tap Scene', id: 'default' }}
    renderScene={this.navigatorRenderScene}
/>

 

Scene

2. For each scene, its a Component, where the life cycle of constructor, componentDidMount, componentUnmount, can be used to trigger specific actions. on each scene, you can use JSX to create the page/view, which could link to functions, like normal js binding:

onActionSelected
onIconClicked
handleClick() {
    if(!this.state.favnumber)
        LocalToastAndroid.show('Please set up your favorite number first', LocalToastAndroid.SHORT);
    else
        LocalToastAndroid.call(this.state.favnumber);
};

Additional actions

3. native react native modules wont cover all functions you request, to create custom module, you can register additional

ReactContextBaseJavaModule

then exposing the method to JS

@ReactMethod
public void call(String number){
.....
}
module.exports = NativeModules.CustomizedModule;

here is the app: https://play.google.com/store/apps/details?id=com.best2lwjj