JS automatically generates a 24-hour time interval with a time span of 60 or 30 minutes

1. The time span is 60 minutes

(1) The time interval is a string

Sometimes it may be necessary to use a 24-hour time interval with a span of 60 minutes, such as the following:

 ['00:00 - 01:00', '01:00 - 02:00', '02:00 - 03:00', '03:00 - 04:00', '04:00 - 05:00', '05:00 - 06:00', '06:00 - 07:00', '07:00 - 08:00', '08:00 - 09:00', '09:00 - 10:00', '10:00 - 11:00', '11:00 - 12:00', '12:00 - 13:00', '13:00 - 14:00', '14:00 - 15:00', '15:00 - 16:00', '16:00 - 17:00', '17:00 - 18:00', '18:00 - 19:00', '19:00 - 20:00', '20:00 - 21:00', '21:00 - 22:00', '22:00 - 23:00', '23:00 - 24:00']

If you write it manually, it is a bit troublesome. At this time, you can use a simple JS function to automatically generate it. The sample code is as follows:

 function generateTimes() {
    let timeArrays = new Array(24).fill("");

    timeArrays.forEach((item, index) => timeArrays[index] = (index < 10 ? '0' + index : index) + ':00' + ' - ' + ((index + 1) < 10 ? '0' + (index + 1) : (index + 1)) + ':00');

    return timeArrays;
}

Of course, the above method can also be abbreviated as the following, only one line of code is needed

 let timeArrays = new Array(24).fill('').map((item, index) => (index < 10 ? '0' + index : index) + ':00' + ' - ' + ((index + 1) < 10 ? '0' + (index + 1) : (index + 1)) + ':00');

(2) The time interval is an array

 let timeArrays = new Array(24).fill(['', '']).map((item, index) => [(index < 10 ? '0' + index : index) + ':00', ((index + 1) < 10 ? '0' + (index + 1) : (index + 1)) + ':00']);
console.log(JSON.stringify(timeArrays));

The resulting time intervals are as follows:

 [["00:00","01:00"],["01:00","02:00"],["02:00","03:00"],["03:00","04:00"],["04:00","05:00"],["05:00","06:00"],["06:00","07:00"],["07:00","08:00"],["08:00","09:00"],["09:00","10:00"],["10:00","11:00"],["11:00","12:00"],["12:00","13:00"],["13:00","14:00"],["14:00","15:00"],["15:00","16:00"],["16:00","17:00"],["17:00","18:00"],["18:00","19:00"],["19:00","20:00"],["20:00","21:00"],["21:00","22:00"],["22:00","23:00"],["23:00","24:00"]]

(3) The time interval is the object

 let timeArrays = new Array(24).fill({}).map((item, index) => {
    return {
        start: (index < 10 ? '0' + index : index) + ':00',
        end: ((index + 1) < 10 ? '0' + (index + 1) : (index + 1)) + ':00'
    }
});
console.log(JSON.stringify(timeArrays));

The resulting time intervals are as follows:

 [{"start":"00:00","end":"01:00"},{"start":"01:00","end":"02:00"},{"start":"02:00","end":"03:00"},{"start":"03:00","end":"04:00"},{"start":"04:00","end":"05:00"},{"start":"05:00","end":"06:00"},{"start":"06:00","end":"07:00"},{"start":"07:00","end":"08:00"},{"start":"08:00","end":"09:00"},{"start":"09:00","end":"10:00"},{"start":"10:00","end":"11:00"},{"start":"11:00","end":"12:00"},{"start":"12:00","end":"13:00"},{"start":"13:00","end":"14:00"},{"start":"14:00","end":"15:00"},{"start":"15:00","end":"16:00"},{"start":"16:00","end":"17:00"},{"start":"17:00","end":"18:00"},{"start":"18:00","end":"19:00"},{"start":"19:00","end":"20:00"},{"start":"20:00","end":"21:00"},{"start":"21:00","end":"22:00"},{"start":"22:00","end":"23:00"},{"start":"23:00","end":"24:00"}]

2. The time span is 30 minutes

If the time span is 30 minutes, that is, 24 hours a day, it needs to be divided into 48 time intervals.

(1) The time interval is a string

 let timeArrays = new Array(48).fill('').map((item, index) => {
    let startVal = index * 30;
    let endVal = (index + 1) * 30;
    let startHour = Math.floor((startVal / 60));
    let startMinute = (startVal % 60);
    let endHour = Math.floor((endVal / 60));
    let endMinute = (endVal % 60);
    let startTime = ((startHour < 10) ? ('0' + startHour) : startHour) + ':' + (startMinute === 0 ? '00' : startMinute);
    let endTime = ((endHour < 10) ? ('0' + endHour) : endHour) + ':' + (endMinute === 0 ? '00' : endMinute);
    
    return startTime + ' - ' + endTime;
});
console.log(timeArrays);

The resulting time intervals are as follows:

 ['00:00 - 00:30', '00:30 - 01:00', '01:00 - 01:30', '01:30 - 02:00', '02:00 - 02:30', '02:30 - 03:00', '03:00 - 03:30', '03:30 - 04:00', '04:00 - 04:30', '04:30 - 05:00', '05:00 - 05:30', '05:30 - 06:00', '06:00 - 06:30', '06:30 - 07:00', '07:00 - 07:30', '07:30 - 08:00', '08:00 - 08:30', '08:30 - 09:00', '09:00 - 09:30', '09:30 - 10:00', '10:00 - 10:30', '10:30 - 11:00', '11:00 - 11:30', '11:30 - 12:00', '12:00 - 12:30', '12:30 - 13:00', '13:00 - 13:30', '13:30 - 14:00', '14:00 - 14:30', '14:30 - 15:00', '15:00 - 15:30', '15:30 - 16:00', '16:00 - 16:30', '16:30 - 17:00', '17:00 - 17:30', '17:30 - 18:00', '18:00 - 18:30', '18:30 - 19:00', '19:00 - 19:30', '19:30 - 20:00', '20:00 - 20:30', '20:30 - 21:00', '21:00 - 21:30', '21:30 - 22:00', '22:00 - 22:30', '22:30 - 23:00', '23:00 - 23:30', '23:30 - 24:00']

(2) The time interval is an array

 let timeArrays = new Array(48).fill(['', '']).map((item, index) => {
    let startVal = index * 30;
    let endVal = (index + 1) * 30;
    let startHour = Math.floor((startVal / 60));
    let startMinute = (startVal % 60);
    let endHour = Math.floor((endVal / 60));
    let endMinute = (endVal % 60);
    let startTime = ((startHour < 10) ? ('0' + startHour) : startHour) + ':' + (startMinute === 0 ? '00' : startMinute);
    let endTime = ((endHour < 10) ? ('0' + endHour) : endHour) + ':' + (endMinute === 0 ? '00' : endMinute);
    
    return [startTime, endTime];
});
console.log(JSON.stringify(timeArrays));

The resulting time intervals are as follows:

 [["00:00","00:30"],["00:30","01:00"],["01:00","01:30"],["01:30","02:00"],["02:00","02:30"],["02:30","03:00"],["03:00","03:30"],["03:30","04:00"],["04:00","04:30"],["04:30","05:00"],["05:00","05:30"],["05:30","06:00"],["06:00","06:30"],["06:30","07:00"],["07:00","07:30"],["07:30","08:00"],["08:00","08:30"],["08:30","09:00"],["09:00","09:30"],["09:30","10:00"],["10:00","10:30"],["10:30","11:00"],["11:00","11:30"],["11:30","12:00"],["12:00","12:30"],["12:30","13:00"],["13:00","13:30"],["13:30","14:00"],["14:00","14:30"],["14:30","15:00"],["15:00","15:30"],["15:30","16:00"],["16:00","16:30"],["16:30","17:00"],["17:00","17:30"],["17:30","18:00"],["18:00","18:30"],["18:30","19:00"],["19:00","19:30"],["19:30","20:00"],["20:00","20:30"],["20:30","21:00"],["21:00","21:30"],["21:30","22:00"],["22:00","22:30"],["22:30","23:00"],["23:00","23:30"],["23:30","24:00"]]

(3) The time interval is the object

 let timeArrays = new Array(48).fill(['', '']).map((item, index) => {
    let startVal = index * 30;
    let endVal = (index + 1) * 30;
    let startHour = Math.floor((startVal / 60));
    let startMinute = (startVal % 60);
    let endHour = Math.floor((endVal / 60));
    let endMinute = (endVal % 60);
    let startTime = ((startHour < 10) ? ('0' + startHour) : startHour) + ':' + (startMinute === 0 ? '00' : startMinute);
    let endTime = ((endHour < 10) ? ('0' + endHour) : endHour) + ':' + (endMinute === 0 ? '00' : endMinute);
    
    return {
        start: startTime,
        end: endTime
    };
});
console.log(JSON.stringify(timeArrays));

The resulting time intervals are as follows:

 [{"start":"00:00","end":"00:30"},{"start":"00:30","end":"01:00"},{"start":"01:00","end":"01:30"},{"start":"01:30","end":"02:00"},{"start":"02:00","end":"02:30"},{"start":"02:30","end":"03:00"},{"start":"03:00","end":"03:30"},{"start":"03:30","end":"04:00"},{"start":"04:00","end":"04:30"},{"start":"04:30","end":"05:00"},{"start":"05:00","end":"05:30"},{"start":"05:30","end":"06:00"},{"start":"06:00","end":"06:30"},{"start":"06:30","end":"07:00"},{"start":"07:00","end":"07:30"},{"start":"07:30","end":"08:00"},{"start":"08:00","end":"08:30"},{"start":"08:30","end":"09:00"},{"start":"09:00","end":"09:30"},{"start":"09:30","end":"10:00"},{"start":"10:00","end":"10:30"},{"start":"10:30","end":"11:00"},{"start":"11:00","end":"11:30"},{"start":"11:30","end":"12:00"},{"start":"12:00","end":"12:30"},{"start":"12:30","end":"13:00"},{"start":"13:00","end":"13:30"},{"start":"13:30","end":"14:00"},{"start":"14:00","end":"14:30"},{"start":"14:30","end":"15:00"},{"start":"15:00","end":"15:30"},{"start":"15:30","end":"16:00"},{"start":"16:00","end":"16:30"},{"start":"16:30","end":"17:00"},{"start":"17:00","end":"17:30"},{"start":"17:30","end":"18:00"},{"start":"18:00","end":"18:30"},{"start":"18:30","end":"19:00"},{"start":"19:00","end":"19:30"},{"start":"19:30","end":"20:00"},{"start":"20:00","end":"20:30"},{"start":"20:30","end":"21:00"},{"start":"21:00","end":"21:30"},{"start":"21:30","end":"22:00"},{"start":"22:00","end":"22:30"},{"start":"22:30","end":"23:00"},{"start":"23:00","end":"23:30"},{"start":"23:30","end":"24:00"}]

3. The time span can be specified arbitrarily

In addition to the common time span of 60 minutes or 30 minutes, sometimes other time spans may be required, so is it possible to write a relatively general method, the parameter is the time span (in minutes), of course it is possible, specifically The implementation code is as follows (only the time interval is a string here, other formats refer to the above):

 function generateTimes(step) {
    let size = Math.floor(24 * 60 / step);
    let timeArrays = new Array(size).fill('').map((item, index) => {
        let startVal = index * step;
        let endVal = (index + 1) * step;
        let startHour = Math.floor((startVal / 60));
        let startMinute = (startVal % 60);
        let endHour = Math.floor((endVal / 60));
        let endMinute = (endVal % 60);
        let startTime = ((startHour < 10) ? ('0' + startHour) : startHour) + ':' + (startMinute === 0 ? '00' : startMinute);
        let endTime = ((endHour < 10) ? ('0' + endHour) : endHour) + ':' + (endMinute === 0 ? '00' : endMinute);
    
        return startTime + ' - ' + endTime;
    });

    return timeArrays;
}

For example, if you want to generate a time interval with a time span of 120 minutes, you can directly pass in 120.

 console.log(generateTimes(120));

The resulting time intervals are as follows:

 ['00:00 - 02:00', '02:00 - 04:00', '04:00 - 06:00', '06:00 - 08:00', '08:00 - 10:00', '10:00 - 12:00', '12:00 - 14:00', '14:00 - 16:00', '16:00 - 18:00', '18:00 - 20:00', '20:00 - 22:00', '22:00 - 24:00']

Note that if the time span is not divisible, the resulting time interval may not fully cover 24 hours.