React.js fetch Giphy

Question

我正在构建一个搜索引擎(和React.js)，在那里我可以使用他们的API查找GIPHY。我是React.js新手，我在正确处理这个代码时遇到了一些困难。

import React from 'react'; //react library
import ReactDOM from 'react-dom'; //react DOM - to manipulate elements
import './index.css';
import SearchBar from './components/Search';
import GifList from './components/SelectedList';

class Root extends React.Component { //Component that will serve as the parent for the rest of the application.

  constructor() {
    super();

    this.state = {
      gifs: []
    }
  }

  handleTermChange(term) {
    console.log(term);
    //---------------------->
    let url = 'http://api.giphy.com/v1/gifs/search?q=${term}&api_key=dc6zaTOxFJmzC';
    fetch(url).
    then(response => response.json()).then((gifs) => {
      console.log(gifs);
      console.log(gifs.length);
      this.setState({
        gifs: gifs
      });
    });//<------------------------- THIS CODE HERE
  };


  render() {
    return (
      <div>
        <SearchBar onTermChange={this.handleTermChange} />
        <GifList gifs={this.state.gifs} />
      </div>
    );
  }
}
ReactDOM.render( <Root />, document.getElementById('root'));

我在控制台中得到了以下错误：Uncaught (承诺) TypeError：_this2.setState不是上的 (index.js:64)函数

任何帮助都是感激的:)谢谢！

Answer 1

this在ES6样式语法中不是自动绑定的.

您必须在构造函数中绑定：`超级()；

this.state = {
    gifs: []
}
this.handleTermChange = this.handleTermChange.bind(this)```

或对所讨论的函数使用箭头函数语法：func = () => {};

参考：https://facebook.github.io/react/blog/2015/01/27/react-v0.13.0-beta-1.html#autobinding