nodejs moment moment-timezone

Use express, moment, moment-timezone

const moment = require('moment-timezone');


app.get('/moment', (req, res) => {
  const datestr = '2020-07-01';

  res.status(200).json({
    local_offset: moment(datestr).utc(),
    local_unix: moment(datestr).unix(),
    zone0_unix: moment(datestr).zone(0).unix(),
    zone8_unix: moment(datestr).zone(8).unix(),
    timezone0_unix: moment.tz(datestr, 'GMT').unix(),
    timezone8_unix: moment.tz(datestr, 'Asia/Taipei').unix(),
  });
});

// No use, just for keep 
function dateForTimezone(offset, d) {
  // Copy date if supplied or use current
  d = d? new Date(+d) : new Date();

  // Use supplied offset or system
  offset = offset || -d.getTimezoneOffset();
  // Prepare offset values
  var offSign = offset < 0? '-' : '+'; 
  offset = Math.abs(offset);
  var offHours = ('0' + (offset/60 | 0)).slice(-2);
  var offMins  = ('0' + (offset % 60)).slice(-2);

  // Apply offset to d
  d.setUTCMinutes(d.getUTCMinutes() - offset);

  return offSign + offHours + ':' + offMins;

  // Return formatted string
  return d.getUTCFullYear() + 
    '-' + ('0' + (d.getUTCMonth()+1)).slice(-2) + 
    '-' + ('0' + d.getUTCDate()).slice(-2) + 
    'T' + ('0' + d.getUTCHours()).slice(-2) + 
    ':' + ('0' + d.getUTCMinutes()).slice(-2) + 
    ':' + ('0' + d.getUTCSeconds()).slice(-2) + 
    '.' + ('000' + d.getUTCMilliseconds()).slice(-3) +
    offSign + offHours + ':' + offMins; 
  
}

IMPORT

Server timezone 0

Client time zone +8


Server run result:

{
  "local_offset": "2020-06-30T16:00:00.000Z",
  "local_unix": 1593532800,
  "zone0_unix": 1593532800,
  "zone8_unix": 1593532800,
  "timezone0_unix": 1593561600,
  "timezone8_unix": 1593532800
}

Client run result:

{
  "local_offset": "2020-07-01T00:00:00.000Z",
  "local_unix": 1593561600,
  "zone0_unix": 1593561600,
  "zone8_unix": 1593561600,
  "timezone0_unix": 1593561600,
  "timezone8_unix": 1593532800
}

Conclusion

moment().zone().unix()  Auto fix zone / utc

moment("").tz("GMT").unix()  Auto fix zone / utc

moment().tz("", "GMT").unix()  No auto fix zone / utc