likeopera-frontend/StoreListener.js

import React from 'react';

import Store from './Store.js';

// "react-redux connect()"-like example
class StoreListener extends React.PureComponent
{
    componentDidMount()
    {
        Store.on(this.update);
    }

    componentWillUnmount()
    {
        Store.un(this.update);
    }

    update = () =>
    {
        var newState = this.mapStateToProps(Store.data);
        for (var i in newState)
        {
            if (this.state[i] != newState[i])
            {
                this.setState(newState);
                return;
            }
        }
    }

    render()
    {
        var props = { ...this.initial, ...this.props, ...this.state };
        return React.createElement(this.wrappedComponent, props);
    }
}

export default function(component, map, initial)
{
    var cl = class extends StoreListener
    {
        constructor(props, context, updater)
        {
            super(props, context, updater);
            this.wrappedComponent = component;
            this.mapStateToProps = map;
            this.initial = initial;
            this.state = map(Store.data);
            this.update = this.update.bind(this);
        }
    };
    return cl;
};