您可以使用 moment.js 创建一个函数来计算经过的时间.

You could create a function using moment.js to calculate elapsed times.

// Day of trip is the trip duration + 1..
function getDayOfTrip(tripStartString, currentDateString) {
    let startDate = moment(tripStartString, 'DD.MM.YYYY');
    let currentDate = moment(currentDateString, 'DD.MM.YYYY');
    return currentDate.diff(startDate, 'days') + 1;
}

let tripStartTime = '7.6.2019';
let tripDates = ['7.6.2019', '8.6.2019', '9.6.2019', '10.6.2019', '11.6.2019', '12.6.2019'];

tripDates.forEach(tripDate => console.log(`Trip date: ${tripDate}, day of trip: ${getDayOfTrip(tripStartTime, tripDate)}`));

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<script src="https://cdnjs.cloudflare.com/ajax/libs/moment-timezone/0.5.25/moment-timezone-with-data-10-year-range.js"></script>