format-time.js

// This is the latest solution to the problem from the prep.
// Make sure to do the prep before you do the coursework
// Your task is to write tests for as many different groups of input data or edge cases as you can, and fix any bugs you find.

function formatAs12HourClock(time) {
  const hours = Number(time.slice(0, 2));
  const minutes = time.slice(-2);
  if (hours > 12) {
    return `${String(hours - 12).padStart(2, "0")}:${minutes}pm`;
  } else if (hours == 12) {
    return `12:${minutes}pm`;
  } else if (hours === 0) {
    return `12:${minutes}am`;
  }
  return `${String(hours).padStart(2, "0")}:${minutes}am`;
}
let currentOutput = formatAs12HourClock("00:01");
let targetOutput = "12:01am";
console.assert(
  currentOutput === targetOutput,
  `current output: ${currentOutput}, target output: ${targetOutput}`
);

const currentOutput2 = formatAs12HourClock("11:59");
const targetOutput2 = "11:59am";
console.assert(
  currentOutput2 === targetOutput2,
  `current output: ${currentOutput2}, target output: ${targetOutput2}`
);
const currentOutput3 = formatAs12HourClock("12:00");
const targetOutput3 = "12:00pm";
console.assert(
  currentOutput3 === targetOutput3,
  `current output: ${currentOutput3}, target output: ${targetOutput3}`
);
currentOutput = formatAs12HourClock("00:00");
targetOutput = "12:00am";
console.assert(
  currentOutput === targetOutput,
  `current output: ${currentOutput}, target output: ${targetOutput}`
);
currentOutput = formatAs12HourClock("04:12");
targetOutput = "04:12am";
console.assert(
  currentOutput === targetOutput,
  `current output: ${currentOutput}, target output: ${targetOutput}`
);
currentOutput = formatAs12HourClock("16:12");
targetOutput = "04:12pm";
console.assert(
  currentOutput === targetOutput,
  `current output: ${currentOutput}, target output: ${targetOutput}`
);