i have an long const values below like this ,is it possible to create in function in typescript to reduce a long const.

export const DepartTime = 
['00.00', '00.30', '01.00', '01.30', '02.00', '02.30', '03.00', '03.30', '04.00', '04.30', '05.00', '05.30', '06.00', '06.30', '07.00', '07.30', '08.00', '08.30', '09.00', '09.30', '10.00', '10.30', '11.00', '11.30', '12.00', '12.30', '13.00',
'13.30', '14.00', '14.30', '15.00', '15.30', '16.00', '16.30', '17.00', '17.30', '18.00', '18.30', '19.00', '19.30',
'20.00', '20.30', '21.00', '21.30', '22.00', '22.30', '23.00', '23.30'
];

These values need to be bind in angular dropdown.

export class SelectOverviewExample implements OnInit {
  days=[];
  times =[];


ngOnInit(){
  [...this.days] = weekdays;
  [...this.times]=DepartTime;
}

in html.

<mat-form-field>
  <mat-select placeholder="select Weekdays">
    <mat-option *ngFor="let time of times" [value]="time">
      {{time}}
    </mat-option>
  </mat-select>
</mat-form-field>

or any third party framework will support

I have tried this and getting below result:

var toInt  = time => ((h,m) => h*2 + m/30)(...time.split(':').map(parseFloat)),
    toTime = int => [Math.floor(int/2), int%2 ? '30' : '00'].join(':'),
    range  = (from, to) => Array(to-from+1).fill().map((_,i) => from + i),
    eachHalfHour = (t1, t2) => range(...[t1, t2].map(toInt)).map(toTime);

console.log(eachHalfHour('00:00', '23:30'))

But i need single digit have start with 00:00,00:30,01.00,01.30 ... 09.30. O/p

by using moment js , i have get a solution but need 0 prefix for single digits

const locale = 'en'; // or whatever you want...
const hours = [];

moment.locale(locale);  // optional - can remove if you are only dealing with one locale

for(let hour = 0; hour < 24; hour++) {
    hours.push(moment({ hour }).format('H:mm'));
    hours.push(
        moment({
            hour,
            minute: 30
        }).format('H:mm')
    );

}
  console.log(hours);

i have an long const values below like this ,is it possible to create in function in typescript to reduce a long const.

export const DepartTime = 
['00.00', '00.30', '01.00', '01.30', '02.00', '02.30', '03.00', '03.30', '04.00', '04.30', '05.00', '05.30', '06.00', '06.30', '07.00', '07.30', '08.00', '08.30', '09.00', '09.30', '10.00', '10.30', '11.00', '11.30', '12.00', '12.30', '13.00',
'13.30', '14.00', '14.30', '15.00', '15.30', '16.00', '16.30', '17.00', '17.30', '18.00', '18.30', '19.00', '19.30',
'20.00', '20.30', '21.00', '21.30', '22.00', '22.30', '23.00', '23.30'
];

These values need to be bind in angular dropdown.

export class SelectOverviewExample implements OnInit {
  days=[];
  times =[];


ngOnInit(){
  [...this.days] = weekdays;
  [...this.times]=DepartTime;
}

in html.

<mat-form-field>
  <mat-select placeholder="select Weekdays">
    <mat-option *ngFor="let time of times" [value]="time">
      {{time}}
    </mat-option>
  </mat-select>
</mat-form-field>

or any third party framework will support

I have tried this and getting below result:

var toInt  = time => ((h,m) => h*2 + m/30)(...time.split(':').map(parseFloat)),
    toTime = int => [Math.floor(int/2), int%2 ? '30' : '00'].join(':'),
    range  = (from, to) => Array(to-from+1).fill().map((_,i) => from + i),
    eachHalfHour = (t1, t2) => range(...[t1, t2].map(toInt)).map(toTime);

console.log(eachHalfHour('00:00', '23:30'))

But i need single digit have start with 00:00,00:30,01.00,01.30 ... 09.30. O/p

by using moment js , i have get a solution but need 0 prefix for single digits

const locale = 'en'; // or whatever you want...
const hours = [];

moment.locale(locale);  // optional - can remove if you are only dealing with one locale

for(let hour = 0; hour < 24; hour++) {
    hours.push(moment({ hour }).format('H:mm'));
    hours.push(
        moment({
            hour,
            minute: 30
        }).format('H:mm')
    );

}
  console.log(hours);

• javascript
• typescript
• ecmascript-6
• momentjs
• angular6

• Sure, you can put a loop in a function and generate that array. Have you tried anything? – Bergi Commented Sep 6, 2018 at 16:02
• I have tried above code but it starts with "0.00","0.30" ,...9:30., but i need "00.30 to 09.30" and remaining things be same.if you find better solution ,more helpful – Mohamed Sahir Commented Sep 6, 2018 at 17:00
• That looks good already! For the remaining problems see stackoverflow./q/8043026/1048572 – Bergi Commented Sep 6, 2018 at 17:27

7 Answers 7

Short answer: change your moment.format to .format('HH:mm'));

You can ensure you get the double digits by just adding an extra 'H' to your existing moment config. ie go from this:

const locale = 'en'; // or whatever you want...
const hours = [];

moment.locale(locale);  // optional - can remove if you are only dealing with one locale

for(let hour = 0; hour < 24; hour++) {
    hours.push(moment({ hour }).format('H:mm'));
    hours.push(
        moment({
            hour,
            minute: 30
        }).format('H:mm')
    );

}
  console.log(hours);

to this

const locale = 'en'; // or whatever you want...
const hours = [];

moment.locale(locale);  // optional - can remove if you are only dealing with one locale

for(let hour = 0; hour < 24; hour++) {
    hours.push(moment({ hour }).format('HH:mm'));
    hours.push(
        moment({
            hour,
            minute: 30
        }).format('HH:mm')
    );

}
  console.log(hours);

Hope that helps! :)

Below Solution work for me:

const hours = [];
Array.apply(null, { length: 24 }).map((value, hour) => {
  hours.push(
    moment({ hour }).format('HH:mm'),
    moment({ hour, minute: 15 }).format('HH:mm'),
    moment({ hour, minute: 30 }).format('HH:mm'),
    moment({ hour, minute: 45 }).format('HH:mm')
  );
});
console.log(hours);

<script src="https://cdnjs.cloudflare./ajax/libs/moment.js/2.29.4/moment.min.js"></script>

Based on your requirements you can push those values to the hours array.

Here is a function that will return the key-value pair based on the given interval(minutes: 60, 30, 15, 10, 5), where the key is in 24-hour format and the display value is in 12-hour format.

 // Interval values can be(minutes): 60 | 30 | 15 | 10 | 5
 function getTimeDDL(intervalMinutes) {
    let formatHour = (hour, minutes) => {
        let minutesPadded = minutes.toString().padStart(2, "0");
        return {
            value: (hour < 10 ? "0" + hour : hour) + `:${minutesPadded}`,
            viewValue: hour < 12 || hour == 24 ? (hour < 24 ? hour : 12) + `:${minutesPadded} AM` : (hour - 12 || 12) + `:${minutesPadded} PM`,
        };
    };

    let timesDDL = [];
    let hour = 1;
    while (hour <= 24) {
        timesDDL.push(formatHour(hour, 0));

        if (hour < 24) {
            let steps = 60 / intervalMinutes;
            let i = 1;
            while (i < steps) {
                let minutes = intervalMinutes * i;
                timesDDL.push(formatHour(hour, minutes));
                i++;
            }
        }

        hour++;
    }
    return timesDDL;
}

 // Interval values can be(minutes): 60 | 30 | 15 | 10 | 5
console.log(getTimeDDL(30));

/** Output 

[
  {
    "value": "01:00",
    "viewValue": "1:00 AM"
  },
  {
    "value": "01:30",
    "viewValue": "1:30 AM"
  },
  ..
  ..
  {
    "value": "24:00",
    "viewValue": "12:00 AM"
  }
]

**/

I don't think you can reduce it. This may not help, but here is JS version :

var foo = [];
for (var i = 0; i <= 48; i++) {
   var n = i%2==0 ? i/2+'.00' : (i+1)/2-1+'.30';
    if(n<10) //zero-left padding
   n = '0'+n;
   foo.push(n);
}
console.log(foo);

Below code works for me I have tried using https://stackoverflow./a/8043061/9516784

    var hrs = [];
    for (var i = 0; i <= 48; i++) {
      var n = i%2==0 ? i/2+'.00' : (i+1)/2-1+'.30';
      if(n<10) {
        n = '0'+n;
      }   
      hrs.push(n);
    }

You can just use division by 2.

let DepartTime = [...Array(48)].map((e, i) => {
    return (i/2<10 ? '0' : '') + (i/2 - i/2 % 1) + (i/2 % 1 != 0 ? '.30' : '.00');
});
console.log(DepartTime);

Passing a string in hh:mm format to your function is making it more plicated than necessary when you could just pass numbers to it.

You can use padStart to ensure a number converted to a string has leading zeroes.

As for the loop, this seems like the perfect situation to use a generator.

function* generateTimes(startHour, stopHour) {
    for (let h = startHour; h < stopHour; ++h) {
        const hh = h.toString().padStart(2, '0');
        yield `${hh}.00`;
        yield `${hh}.30`;
    }
}

console.log([...generateTimes(0, 24)]);