获取图形后过滤数据

Question

我正在使用 API 从数据库中获取数据，这些数据将用于在图表中显示。下面是 API 的格式。我希望我的图表只显示时间而不是时区日期。有没有办法将值从字符串更改为 int？

API data
[{"time":"2022-01-13T15:26:20.129055+08:00","location":"north","value":"30","sensorType":null,"type":"temperature"},
{"time":"2022-01-13T15:54:31.718588+08:00","location":"north","value":"35","sensorType":null,"type":"temperature"}]

code for fetch and x,y for plotting graph
 const [data, setData] = useState([]);

  useEffect(() => {
    asyncFetch();
  }, []);

  const asyncFetch = () => {
      fetch('api')
      .then((response) => response.json())
      .then((json) => setData(json))
      .catch((error) => {
        console.log('fetch data failed', error);
      });
  };
    const config = {
        data,
        xField: 'time',
        yField: 'value',

Answer 1

您可以从时间字符串创建一个 Date 对象并根据需要获取时间。

像下面这样尝试。

const apiData = {"time":"2022-01-13T15:26:20.129055+08:00","location":"north","value":"30","sensorType":null,"type":"temperature"};

const timeStamp = new Date(apiData.time);
 
// int value of time in millis
console.log(timeStamp.getTime());

// formatted time
console.log(`${timeStamp.getHours()}:${timeStamp.getMinutes()}`);

在您的 then 块中更新数据，然后再将其设置为 data.

.then((json) =>
    setData(
        (json || []).map((item) => {
            const timeStamp = new Date(item.time);
            return {
                ...item,
                time: `${timeStamp.getHours()}:${timeStamp.getMinutes()}`,
            };
        })
    )
)

获取图形后过滤数据

filtering data after fetch for graph

reactjs

fetch

fetch-api