Javascript Homework #5

time-adder.js

const timeAdder = (value1, label1, value2, label2) => {
  if (typeof value1 !== "number" || typeof value2 !== "number") {
    console.log("Values must be numbers");
    return false; // must be numbers
  }
  if (/\./.test(value1) || /\./.test(value2)) {
    console.log("Values must be integers");
    return false; // must be integers
  }
  if (value1 < 0 || value2 < 0) {
    console.log("Values must be positive");
    return false; // must be positive
  }
  const units = ["second", "seconds", "minute", "minutes", "hour", "hours", "day", "days"];
  if (typeof label1 !== "string" || typeof label2 !== "string") {
    console.log("Only string types are allowed for labels")
    return false; // only strings allowed
  }
  if (units.indexOf(label1) === -1 || units.indexOf(label2) === -1) {
    console.log("Only the specific set of strings is allowed for labels")
    return false; // only specific labels allowed
  }
  if ((value1 === 1 && /s$/.test(label1)) ||
    (value2 === 1 && /s$/.test(label2))) {
    console.log("Check your labels for proper pluralization when necessary, i.e. use 1 hour instead of 1 hours, or 25 minutes insetad of 25 minute");
    return false; // make sure pluralization is in place where required
  }
  const i1 = units.indexOf(label1);
  const i2 = units.indexOf(label2);
  
  let args = [value1, label1, value2, label2];
  if (i1 > i2) {
    // smaller units first
    args = [value2, label2, value1, label1];
  }
  switch (args[1]) {
    case "minute":
    case "minutes":
      args[0] *= 60;
      break;
    case "hour":
    case "hours":
      args[0] *= 3600;
      break;
    case "day":
    case "days":
      args[0] *= 86400;
      break;
  }
  switch (args[3]) {
    case "minute":
    case "minutes":
      args[2] *= 60;
      break;
    case "hour":
    case "hours":
      args[2] *= 3600;
      break;
    case "day":
    case "days":
      args[2] *= 86400;
      break;
  }
  args[1] = args[3] = "seconds";
  let totalSeconds = args[0] + args[2];
  let numSeconds = totalSeconds;
  let numDays = 0, numHours = 0, numMinutes = 0;
  if (numSeconds >= 86400) {
    numDays = Math.floor(numSeconds / 86400);
  }
  numSeconds -= (numDays * 86400);
  if (numSeconds >= 3600) {
    numHours = Math.floor(numSeconds / 3600);
  }
  numSeconds -= (numHours * 3600);
  if (numSeconds >= 60) {
    numMinutes = Math.floor(numSeconds / 60);
  }
  numSeconds -= (numMinutes * 60);
  
  let unit = "seconds";
  if (numSeconds === 0) {
    unit = "minutes";
  }
  if (numSeconds === 0 && numMinutes === 0) {
    unit = "hours";
  }
  if (numSeconds === 0 && numMinutes === 0 && numHours === 0) {
    unit = "days";
  }
  
  let res = [totalSeconds, unit];
  switch (unit) {
    case "days":
      res[0] = numDays;
      break;
    case "hours":
      res[0] = numHours + (numDays * 24);
      break;
    case "minutes":
      res[0] = numMinutes + (numHours * 60) + (numDays * 24);
      break;
  }
  
  if (res[0] === 1) {
    res[1] = res[1].substring(0, res[1].length - 1);
  }
  
  console.log("Days: " + numDays + ", Hours: " + numHours + ", Minutes: " + numMinutes + ", Seconds: " + numSeconds);
  console.log(res);

  return res;
};

timeAdder(2, "hours", 22, "hours");      // <-- [1, "day"]
timeAdder(6, "hours", 20, "hours");      // <-- [26, "hours"]
timeAdder(60, "minutes", 1, "hour");     // <-- [2, "hours"]
timeAdder(10, "minutes", 50, "minutes"); // <-- [1, "hour"]
timeAdder(50, "seconds", 10, "minutes"); // <-- [650, "seconds"]