如何设置反应状态？

Question

我是新来的反应者，我正在尝试使用Urban Dictionary API制作Web应用程序字典。问题是当我输出响应参数时，它会显示值，但是当我将状态设置为“定义”时，出现错误，提示Uncaught TypeError: Cannot read property 'setState' of undefined

unirest
  .get("https://mashape-community-urban-dictionary.p.rapidapi.com/define")
  .query({ term: "explore" })
  .headers({
    "x-rapidapi-host": "mashape-community-urban-dictionary.p.rapidapi.com",
    "x-rapidapi-key": "9196cfb95cmsh64bb4272c1f6e0bp1aa2bejsnb01c091dff35",
    useQueryString: true,
  })
  .end(function (res) {
    // displaying
    console.log(res.body); 

    //cannot read | Undefined
    this.setState({
      define: res.body,
    });
  });