反应中的脚本加载 [英] Script load in react

问题描述

我想从 CDN 加载脚本，然后在 React 中执行该脚本公开的函数:

I want to load the script from a CDN and then execute a function exposed by that script in React:

componentWillMount() {
    console.log('componentWillMount is called');
    const script = document.createElement('script');
    script.src = 'https://foo.azurewebsites.net/foo.js';
    document.body.appendChild(script);
}


componentDidMount() {
    console.log('componentDidMount is called');
    window.foo.render({
        formId: '77fd8848-791a-4f13-9c82-d24f9290edd7',
    }, '#container');
}


render() {
    console.log('render is called');
    return (
        <div id="container"></div>
    );
}

脚本有时需要时间来加载(通常是第一次)，当 componentDidMount() 被调用时，foo"不可用，我收到这样的错误:

The script sometimes takes time to load (generally first time) and when componentDidMount() is called "foo" is not available and I get an error like this:

TypeError: 无法读取未定义的属性 'render'

TypeError: Cannot read property 'render' of undefined

如何确保在成功加载脚本后调用 componentDidMount()?

How can I assure that componentDidMount() is called once the script is loaded successfully?

推荐答案

我认为在 componentWillMount() 或 componentDidMount() 中加载脚本不是一个好主意，根据 React 组件规范和生命周期.

I don't think it's a good idea to load scripts in componentWillMount() or componentDidMount(), according to React Component Specs and Lifecycle.

以下代码可能对您有所帮助.

The code below may help you.

function new_script(src) {
  return new Promise(function(resolve, reject){
    var script = document.createElement('script');
    script.src = src;
    script.addEventListener('load', function () {
      resolve();
    });
    script.addEventListener('error', function (e) {
      reject(e);
    });
    document.body.appendChild(script);
  })
};
// Promise Interface can ensure load the script only once.
var my_script = new_script('http://example.com/aaa.js');

class App extends React.Component {

  constructor(props) {
    super(props);
    this.state = {
      status: 'start'
    };
  }

  do_load = () => {
    var self = this;
    my_script.then(function() {
      self.setState({'status': 'done'});
    }).catch(function() {
      self.setState({'status': 'error'});
    })
  }

  render() {
    var self = this;
    if (self.state.status === 'start') {
      self.state.status = 'loading';
      setTimeout(function () {
        self.do_load()
      }, 0);
    }

    return (
      <div>{self.state.status}   {self.state.status === 'done' && 'here you can use the script loaded'}</div>
    );
  }
}

这篇关于反应中的脚本加载的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！