React，JavaScript中的Catch 504（网关超时）错误

Question

我有一个工作API来从服务器获取项目，如下所示。我正在使用React来使用这些数据。现在，我希望捕获所有以5__开头的服务器错误并显示一条消息，例如＆＃34;没有与互联网连接＆＃34;或类似的东西。

 export const GetItems = (operand, searchValue) => {
      const trimmedValue = searchValue.trim();
      let combinedResults;
      // make 2 API calls to search on both item_name and code;
      // then combine them;
      // there is no API method to do this, that I could find
      return getItemsByName(operand, trimmedValue)
      .then(result => (
        (combinedResults = [].concat(result))
      ))
      .then(() => getItemsByCode(operand, trimmedValue))
      .then(result => (
        (combinedResults = combinedResults.concat(result))
      ));
    };

目前，我需要查看控制台以检查连接是否存在问题。

更新为@Dane要求

const getItemsByCode = (operand, searchValue) => (
  FetchToJson(BuildCodeSearchUrl(operand, searchValue))
);

它只是调用一种方法来构建URL。你可以认为一切都运行良好，如果有连接就得到响应。

Answer 1

使用catch()：

return getItemsByName(operand, trimmedValue)
      .then(result => (
        (combinedResults = [].concat(result))
      ))
      .then(() => getItemsByCode(operand, trimmedValue))
      .then(result => (
        (combinedResults = combinedResults.concat(result))
      ))
      .catch((error) => {
        if (error.response) { // if there is response, it means its not a 50x, but 4xx

        } else {   // gets activated on 50x errors, since no response from server
          // do whatever you want here :)
        }            
      });