React 16使用了Portals时，Server Side Render碰到的问题

最近发布的React 16支持Portals(https://facebook.github.io/react/docs/portals.html),也就是支持将子组件render到其它任何地方。Vuejs也支持类似的功能，见https://github.com/LinusBorg/portal-vue。

昨天尝试了下Portals功能，demo如下

import React,{Component} from 'react';
import ReactDOM from 'react-dom';
import jsdom from 'jsdom';

const { JSDOM } = jsdom;
const dom = new JSDOM(`
    <!DOCTYPE html>
    <html>
        <body>
            <div id="app"></div>
            <div id="domNode"></div>
        </body>
    </html>
`);
const document = dom.window.document;
const htmlNode = document.querySelector("html");
const appNode = document.querySelector("#app");
const domNode = document.querySelector("#domNode");

class Portals extends Component {
    render() {
        return ReactDOM.createPortal(
            this.props.children,domNode,);
    }
}

ReactDOM.render(
    <Portals>
        <h1>hello</h1>
        <span>Hello React 16.</span>
    </Portals>,appNode
);
console.log('htmlNode -> ',htmlNode.outerHTML);

输出结果如下：

htmlNode ->  <html><head></head><body>
            <div id="app"></div>
            <div id="domNode"><h1>hello</h1><span>Hello React 16.</span></div>


</body></html>

可以看到使用了Portals后，<Portals>组件的children render到domNode中了，而不是render到app节点中。

下面来看下在使用服务端渲染时的代码：

import React,{Component} from 'react';
import ReactDOM from 'react-dom';
import ReactDOMServer from 'react-dom/server';
import jsdom from 'jsdom';

const { JSDOM } = jsdom;
const dom = new JSDOM(`
    <!DOCTYPE html>
    <html>
        <body>
            <div id="app"></div>
            <div id="domNode"></div>
        </body>
    </html>
`);
const document = dom.window.document;
const htmlNode = document.querySelector("html");
const domNode = document.querySelector("#domNode");

class Portals extends Component {
    render() {
        return ReactDOM.createPortal(
            this.props.children,);
    }
}

const str = ReactDOMServer.renderToString(
    <Portals>
        <h1>hello</h1>
        <span>Hello React 16.</span>
    </Portals>
);
console.log('str',str);
console.log('htmlNode -> ',htmlNode.outerHTML);

代码主体功能没差别，主要是ReactDOM.render改成了ReactDOMServer.renderToString,

但这次render没有成功，具体错误信息如下：

D:\work_react\react16-demo\node_modules\.npminstall\fbjs\0.8.16\fbjs\lib\invariant.js:49
    throw error;
    ^

Invariant Violation: Objects are not valid as a React child (found: object with keys {$$typeof,key,children,containerInfo,implementation}). If you
 meant to render a collection of children,use an array instead.
    in Portals
    at invariant (D:\work_react\react16-demo\node_modules\.npminstall\fbjs\0.8.16\fbjs\lib\invariant.js:42:15)
    at traverseAllChildrenImpl (D:\work_react\react16-demo\node_modules\.npminstall\react\16.0.0\react\cjs\react.development.js:830:7)
    at traverseAllChildren (D:\work_react\react16-demo\node_modules\.npminstall\react\16.0.0\react\cjs\react.development.js:858:10)
    at mapIntoWithKeyPrefixInternal (D:\work_react\react16-demo\node_modules\.npminstall\react\16.0.0\react\cjs\react.development.js:934:3)
    at toArray (D:\work_react\react16-demo\node_modules\.npminstall\react\16.0.0\react\cjs\react.development.js:981:3)
    at ReactDOMServerRenderer.render (D:\work_react\react16-demo\node_modules\.npminstall\react-dom\16.0.0\react-dom\cjs\react-dom-server.node.developme
nt.js:2757:26)
    at ReactDOMServerRenderer.read (D:\work_react\react16-demo\node_modules\.npminstall\react-dom\16.0.0\react-dom\cjs\react-dom-server.node.development
.js:2722:19)
    at Object.renderToString (D:\work_react\react16-demo\node_modules\.npminstall\react-dom\16.0.0\react-dom\cjs\react-dom-server.node.development.js:29
80:25)
    at Object.<anonymous> (D:/work_react/react16-demo/demo/portalsServerSide.js:29:28)
    at Module._compile (module.js:571:32)

还没有找到具体的原因。

React 16使用了Portals时，Server Side Render碰到的问题

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