Render Happening Before ComponentWillMount

Question

I am trying to load some source data before rendering my components in ReactJs. I also use architecture Fluxfor this process. Here is mine container:

class MemoryApp extends React.Component {
    constructor(props){
        super(props);
        MemoryActions.getInit();
        this.state = {};

    }

    componentWillMount(){
        MemoryStore.on("init", () => {
            this.setState({
                memory: MemoryStore.getInit()
            });
        })
    }

    render(){
        return (
            <div>
                <button type="button">Get Random Memory</button>
                <h1>Memory App</h1>
                <MemoryImage memory={this.state.memory}/>
                <MemoryText memory={this.state.memory}/>
            </div>
        );
    }
}

So, in this file, I call an action getInit()that calls the API to retrieve some data. When this data is received, the event initwill be emitted by the symbol store:

class MemoryStore extends EventEmitter {

    getInit(){
        return this.memory_response;
    }

    initLoad(response){
        this.memory_response = response;
        this.emit("init");
    }

    handleActions(action){

        switch (action.type) {
            case MemoryConstants.GET_INIT_RESPONSE:{
                this.initLoad(action.response);
                break;
            }
            default:{
                return true;
            }
        }
    }

}

const memoryStore = new MemoryStore();
dispatcher.register(memoryStore.handleActions.bind(memoryStore));
export default memoryStore;

Then, as you can see, we set the state then to componenWillMount(). Then I want to display the components. One component is image: import React from 'react'

export default class MemoryImage extends React.Component{
    renderItems(){

        console.log(this.props); // ===> Here is my console.log
        if (this.props.memory){
            return this.props.memory[0].description;
        } else {
            return "Nothing";
        }
    }

    renderImage(){
        if (this.props.memory){
            return this.props.memory[0].image;
        } else {
            return "Nothing";
        }
    }

    render(){
        return(
            <div>
                <p>{this.renderItems()}</p>
                <img style={{width:'200px'}} src={this.renderImage()} alt="none"/>
            </div>
        );
    }
}

And after entering the console ...

memory-image.js:10 {memory: undefined}
memory-image.js:10 {memory: Array(1)}

, , componentWillMount(). , , , componentWillMount(). ?

Answer 1

, , en event listener:

MemoryStore.on("init", () => {
    this.setState({
        memory: MemoryStore.getInit()
    });
})

( ) .

(IMO) :

getMemoryItems() {
    if (this.state.memory) {
        return <div>
            <MemoryImage memory={this.state.memory}/>
            <MemoryText memory={this.state.memory}/>
        </div>
    }
}

render(){
    return (
        <div>
            <button type="button">Get Random Memory</button>
            <h1>Memory App</h1>
            { this.getMemoryItems() }
        </div>
    );
}

:

render(){
    return (
        <div>
            <button type="button">Get Random Memory</button>
            <h1>Memory App</h1>
            { this.state.memory ? <MemoryImage memory={this.state.memory}/> : '' }
            { this.state.memory ? <MemoryText memory={this.state.memory}/> : '' }
        </div>
    );
}

Answer 2

, componentWillMount, , (.. init ). componentWillMount (.. render ..). , memory.

, , memory, ,

render(){
        if(!this.state.memory){
           // Just wait for the memory to be available
           return null;
        }
        return (
            <div>
                <button type="button">Get Random Memory</button>
                <h1>Memory App</h1>
                <MemoryImage memory={this.state.memory}/>
                <MemoryText memory={this.state.memory}/>
            </div>
        );
    }