How to Convert string time in 12-Hr format to integer then back-CodePudding

I want to convert a 12-hour format time into a string, add some minutes, then convert back to string. My user will be entering a time as a sting example 8:03 AM this time needs to converted into an integer with 9 minutes added to it then converted back to the same 12-hour format just 9 minutes into the future.

I've tried to make a Date obj using the string time, but when I do the Date constructor says I am using an invalid date.

new Date("8:03 AM")

What I tried after that was adding a speicifc date to the time

new Date("09/10/2022 8:03 AM")

That worked to create a Date obj and then I would try to get just the time using .getTime() and pass that into my intToHHMM function.

const intToHHMM = function (time) {
    var sec_num = parseInt(time, 10); // don't forget the second param
    var hours   = Math.floor(sec_num / 3600);
    var minutes = Math.floor((sec_num - (hours * 3600)) / 60);
    var seconds = sec_num - (hours * 3600) - (minutes * 60);

    if (hours   < 10) {hours   = "0" hours;}
    if (minutes < 10) {minutes = "0" minutes;}
    if (seconds < 10) {seconds = "0" seconds;}
    return hours ':' minutes;
}

But I am getting a weird return that definitely is not hh:mm format.

Can someone lend a hand, I appreciate the help in advance!

CodePudding user response：

Just check this out.

var date = new Date("09/10/2022 8:03 AM");
var options = {
  hour: 'numeric',
  minute: 'numeric',
  hour12: true
};
var timeString = date.toLocaleString('en-US', options);
console.log(timeString);

function addMinutes(date, minutes) {
    return new Date(date.getTime()   minutes*60000);
}
var timePlusNineMinString=addMinutes(date,9).toLocaleString('en-US', options);
console.log(timePlusNineMinString);

CodePudding user response：

check this function, pass any time and it will add minsToAdd minutes to start. Correct any mistakes when see them.

function addMins(start, minsToAdd) {
  let am_pm = start.split(" ")[1]
  let [hr, min] = start.split(" ")[0].split(":")
  let future = ""
  min = parseInt(min)   minsToAdd
  if (min > 59) {
    min = min - 60
    hr = parseInt(hr)   1
    am_pm = hr > 11 ?
      am_pm === "PM" ? "AM" : "PM" :
      am_pm === "AM" ? "PM" : "AM";
    hr = hr > 12 ? hr - 12 : hr;
    future = [
      `${parseInt(hr)}`.length === 1 ? `0${hr}` : `${hr}`,
      `${min}`.length === 1 ? `0${min}` : `${min}`,
      am_pm
    ].join(":")
  } else {
    future = [`${hr}`.length === 1 ? `0${hr}` : `${hr}`,
      `${min}`.length === 1 ? `0${min}` : `${min}`,
      am_pm
    ].join(":")
  }
  return future

}

console.log(addMins("11:56 AM", 9)) //12:05:PM
console.log(addMins("11:56 PM", 9)) //12:05:AM
console.log(addMins("19:03 PM", 9)) //19:12:PM

CodePudding user response：

Generally I can say, you can use momentjs. but if you can share the part of your code there might be better and more accurate solutions.