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Challenge 64: 24 to 12

curriculum/challenges/english/blocks/daily-coding-challenges-javascript/68cae5b538ff798bbd4da002.md

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--description--

Given a string representing a time of the day in the 24-hour format of "HHMM", return the time in its equivalent 12-hour format of "H:MM AM" or "H:MM PM".

  • The given input will always be a four-digit string in 24-hour time format, from "0000" to "2359".

--hints--

to12("1124") should return "11:24 AM".

js
assert.equal(to12("1124"), "11:24 AM");

to12("0900") should return "9:00 AM".

js
assert.equal(to12("0900"), "9:00 AM");

to12("1455") should return "2:55 PM".

js
assert.equal(to12("1455"), "2:55 PM");

to12("2346") should return "11:46 PM".

js
assert.equal(to12("2346"), "11:46 PM");

to12("0030") should return "12:30 AM".

js
assert.equal(to12("0030"), "12:30 AM");

--seed--

--seed-contents--

js
function to12(time) {

  return time;
}

--solutions--

js
function convertHours(hours) {
  if (hours === 0) return 12;
  if (hours > 12) return hours - 12;
  return hours;
}

function to12(time) {
  const hours = parseInt(time.slice(0, 2), 10);
  const minutes = time.slice(2);
  const period = hours < 12 ? 'AM' : 'PM';

  return `${convertHours(hours)}:${minutes} ${period}`;
}