This react component library is possible to get asynchronous data before rendering. this is like next.js :rocket:

I have made async-react-router like Routing of Next.js in the past. But, that library is very complicated. In order to make it more simple, I made next-props as a component library, not routing library. Instead, SSR is not supported.

Feature

• This is component library of React.
• Support React version 16.
• Support async/await like next.js.
• No depend on react-router.
• No depend on rxjs.
  • But, You can combine asynchronous library like rxjs.
• No Support SSR.
  • In the case of SSR, it is not possible to deal with asynchronous because it relies on routing.
  • Asynchronous is very difficult...
• Support view for initial rendering.

Demo

• with React Router
• with Redux

Example

import React from "react";
import { render } from "react-dom";
import { HashRouter, Switch, Route, Link } from 'react-router-dom';
import NextProps from "next-props";

// Sleep
function sleep(ms) {
    return new Promise((resolve) => setTimeout(resolve, ms));
}

class Home extends React.Component {
    static async getInitialProps(props) {
        await sleep(1000);
        return {
            message: 'Home is one second sleep.'
        };
    }

    render() {
        return (
            <div>{this.props.message}</div>
        );
    };
}

render(
    (
        <HashRouter>
            <Switch>
                <Route path="/" exact render={(props) => <NextProps {...props} component={Home} />} />
            </Switch>
        </HashRouter>
    ),
    document.getElementById('app')
);

API

NextProps props

props.component

You specify the component you want to get data asynchronously.

<NextProps component={HomeComponent}/>

props.streamer((load, setInitialProps) => any)

You can use this hook api to control the asynchronous order. The example is RxJS.

// Set RxJS
import { Subject } from "rxjs";
const stream = new Subject();

const streamer = (load, setInitialProps) => {
     stream
         .switchMap(load)
         .subscribe(setInitialProps);
 };

<NextProps component={HomeComponent} streamer={streamer} fireStreamer={fireStreamer}/>

load is Promise to handle getInitialProps(props).
setInitialProps set the data acquired by load as initialProps.

props.fireStreamer(() => any)

Setting props.streamer makes it Observable, so you also need to set fire.

const fireStreamer = () => {
    stream.next();
};

<NextProps component={HomeComponent} streamer={streamer} fireStreamer={fireStreamer}/>

props.firstRender(() => any)

Rendering does not stop even if it is asynchronous. Please use this function if you want to make it a specific view during initial rendering.

const firstRender = () => {
  return (
      <div className="text-center" style={{margin: "100px 0"}}>
          <i className="fa fa-cog fa-spin fa-5x fa-fw"/>
      </div>
  );
};

<NextProps component={HomeComponent} firstRender={firstRender}/>

Function in props.component of NextProps

component.getInitialProps(props)

You can get data considering async / await using getInitialProps(props).

class HomeComponent extends React.Component {
    static async getInitialProps(props) {
        await sleep(1000);
        return {
            message: 'Home is one second sleep.'
        };
    }
}

component.initialPropsWillGet()

initialPropsWillGet() is called before getInitialProps(props).
async/await is not supported.

class HomeComponent extends React.Component {
    initialPropsWillGet() {
        console.log("before `getInitialProps()`");
    }
}

component.initialPropsDidGet()

initialPropsDidGet() is called after getInitialProps(props).
async/await is not supported.

class HomeComponent extends React.Component {
    initialPropsDidGet() {
        console.log("after `getInitialProps()`");
    }
}