尝试从 node.js 中的 url 获取时，获取“无法读取未定义的属性‘长度’”

Question

所以我试图创建一个 Discord-Bot，它能够在 Urbandictionary 上查找定义..但是在尝试从他们的 api 获取 json 后我收到了一个错误。

const args = Array.prototype.slice.call(commandArgs);
    if (!args.length) {
    return message.channel.send('You need to supply a search term!');
    }

    const query = querystring.stringify({ term: args.join(' ') });

    const body  = await fetch(`https://api.urbandictionary.com/v0/define${query}`).then(response => response.json());

    console.log(fetch(`https://api.urbandictionary.com/v0/define${query}`).then(response => response.json()));

    if (!body.list.length) {
        return message.channel.send(`No results found for **${args.join(' ')}**.`);
    }

    const [answer] = body.list;

    const embed = new Discord.RichEmbed()
        .setColor('#EFFF00')
        .setTitle(answer.word)
        .setURL(answer.permalink)
        .addField('Definition', trim(answer.definition, 1024))
        .addField('Example', trim(answer.example, 1024))
        .addField('Rating', `${answer.thumbs_up} thumbs up. ${answer.thumbs_down} thumbs down.`);

    message.channel.send(embed);
    }

错误如下所示：

    (node:11948) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'length' of undefined
    at Client.client.on (C:\Users\Johannes\Desktop\Vladimir\main.js:176:18)
    at processTicksAndRejections (internal/process/next_tick.js:81:5)
(node:11948) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:11948) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

中间的 console.log() 函数只是说：“Promise { pending }”

Answer 1

如果我们从未遇到过编码难题，那么我们可能还不够努力。 而不是放弃，你寻求帮助。 足够聪明，可以做所有让你处于有利位置的事情。

在您的代码中，您有一个 await 命令。 为此，异步需要放置在外部函数的开头之前。 请记住， await 仅适用于承诺。 另请注意，您在 body 旁边获取了一次，然后在控制台语句中再次获取。 当我们只需要一个请求时，这将导致两个请求。 希望下面更新的片段可以帮助您。

getUrbanDictionaryDefs = async function() {
  const args = Array.prototype.slice.call(commandArgs);
  if (!args.length) {
    return message.channel.send("You need to supply a search term!");
  }

  const query = querystring.stringify({ term: args.join(" ") });

  let body;

  try {
    body = await fetch(`https://api.urbandictionary.com/v0/define${query}`);
  } catch (err) {
    console.log(err);
    return;
  }

  body = body.json();

  console.log(body);

  if (!body.list.length) {
    return message.channel.send(`No results found for **${args.join(" ")}**.`);
  }

  const [answer] = body.list;

  const embed = new Discord.RichEmbed()
    .setColor("#EFFF00")
    .setTitle(answer.word)
    .setURL(answer.permalink)
    .addField("Definition", trim(answer.definition, 1024))
    .addField("Example", trim(answer.example, 1024))
    .addField(
      "Rating",
      `${answer.thumbs_up} thumbs up. ${answer.thumbs_down} thumbs down.`
    );

  message.channel.send(embed);
};