How to convert time to 24 hours format in javascript | letsbug

    Today is we are doing something which is the most basic thing that you come across in your everyday life. But barely notice it. And while you are learning programming you may have sometimes ignored it. It is time converting or changing it to different format.

    And we will see 

How To Convert Time To 24 Hours Military Format In Javascript 

    So, lets get started by creating a function. Name the function anything you want mine is timeConverter(time). We are passing time to the function. 

    Time which we are passing is a string like this "1:00:05AM". Now in the function first lets extract some important data from the input. Like we will extract hours, minutes and seconds.

    Then as the format of input time is in 12 hours that means we will have AM/PM to differentiate between day and night. So, we will extract that data also. The variable half stores AM or PM.

    After we have all the data extracted we can now convert it to 24 hours format. By first checking that if hours in the input is 12 or not. If so then we will overwrite it to "00" as in 24 hours format time starts from "00" hours. 

    Next comes checking that if half is "PM" or "AM" and if it is  "PM" means it is time where in the 24 hours it shows like 13, 14, etc. hours. So If it is "PM" we add 12 to the hours so it will become the hours + 12.

    Example: If the input is "1:00:05PM" 

                First we will extract 1 as hour, 00 as minutes, 05 as seconds and AM/PM as half. As hour here is not 12 so our first if check will come into play. But the half is PM so we will add 12 to the hour which is 1 + 12 which gives us 13 hours which what we want. So out output will be like "13:00:05" 

    Now coming to our function after adding 12 to hours we will return that hour, minutes, and seconds. And that's it.

    Here is the code   

function timeConverter(time) {
   let [hrs, min, sec] = time.slice(0, -2).split(":")
   let half = time.slice(-2)
   if(parseInt(hrs) == 12){
       hrs = "00"
   }
   if(half == "PM"){
       hrs = parseInt(hrs) + 12
   }
   return `${hrs}:${min}:${sec}`
}
console.log(timeConverter("2:00:05PM"))

Output: "14:00:05"