尝试使用特定时区转换 UTC 时间

Question

I am currently creating an app through React which connects to the OpenWeatherAPI. The app is when someone types in there location it pulls the weather of their specific location. The issue I am having is converting the timestamp of the specific location to a local time. I have used MomentJs, but the time keeps up coming wrong. The issue for example if someone chooses Tokyo, Japan I want it to show that the sunrise will be 6:50 am their local time. Right now I am getting back Mon Dec 28 2020 16:50:24 GMT-0500 (Eastern Standard Time).

This is the API snippet:

{
  "dt": 1609176171,
    "sys": {
        "type": 1,
        "id": 8074,
        "country": "JP",
        "sunrise": 1609192224,
        "sunset": 1609227369
    },
    "timezone": 32400,
    "id": 1862143,
    "name": "Horinouchi",
    "cod": 200
}

Answer 1

You can create a date for the sunrise by adding the timezone value.

The example below will produce a date and time in the timezone of the weather record (Horinouchi), NOT the timezone of the user.

 const data = { "dt": 1609176171, "sys": { "type": 1, "id": 8074, "country": "JP", "sunrise": 1609192224, "sunset": 1609227369 }, "timezone": 32400, "id": 1862143, "name": "Horinouchi", "cod": 200 }; // extract sunrise and timezone offset in UNIX epoch seconds const { sys: {sunrise}, timezone } = data; // create Date object for sunrise with timezone offset const srTime = new Date((sunrise+timezone)*1000); // convert number to a 2-digit string const twoDigits = (val) => { return ('0' + val).slice(-2); }; const year = srTime.getUTCFullYear(); const month = twoDigits(srTime.getUTCMonth()+1); const dayOfMonth = twoDigits(srTime.getUTCDate()); const hours = twoDigits(srTime.getUTCHours()); const minutes = twoDigits(srTime.getUTCMinutes()); const seconds = twoDigits(srTime.getUTCSeconds()); console.log(`${year}-${month}-${dayOfMonth} ${hours}:${minutes}:${seconds}`);

Note that the date will be in UTC time, so be sure to display it for the user that way (ie don't display it with a local offset).

To display the UTC date, use Date.prototype:

• .getUTCDate()
• .getUTCMonth()
• .getUTCDay()
• .getUTCHours()
• .getUTCMinutes()
• .getUCSeconds()