how to format time like 13:15 to 13.5 in javascript

Question

hello guys i need to format time to values like this:

00:00 ==> 0
00:15 ==> 0.25
00:30 ==> 0.5
00:45 ==> 0.75
....
16:00 ==> 16
16:15 => 16.25
16:30 => 16.5
16:45 => 16.75

i already used switch case:

switch (time) {
        case "00:00":
            return { value: 0, time: time };
        case "00:30":
            return { value: 0.5, time: time };
        case "01:00":
            return { value: 1, time: time };
        case "01:30":
            return { value: 1.5, time: time };
        case "02:00":
            return { value: 2, time: time };
        case "02:30":
            return { value: 2.5, time: time };
        case "03:00":
            return { value: 3, time: time };
....

but i think its not optimized any better idea?

Answer 1

You could divide the minutes by the hour length.

const
    formatTime = s => +s.split(':').map((d, i) => i ? d / 0.6 : d).join('.');


console.log(formatTime('00:45'));
console.log(formatTime('01:15'));

Answer 2

You could use replace callback, replacing all except an initial zero, then format the two components to a decimal number and format with 2 decimals (using toFixed). This works for all minutes (from 0 to 59).

Demo:

const formatTime = s => s.replace(/([1-9]\d?):(.+)/, (_, m, s) => (+m+s/60).toFixed(2));

// Demo
for (let min = 0; min < 40; min++) {
    const time = '09:' + (min < 10 ? "0" + min : min);
    console.log(time, "=>", formatTime(time));
}