javascript clock

clock.exs

defmodule Clock do
  def start do
    time = {12, 0, 0}
    print_time(time)
    :timer.sleep(1_000)
    increment_time(time)
  end

  defp increment_time(time) do
    time = update_seconds(time)
    print_time(time)
    :timer.sleep(1_000)
    increment_time(time)
  end

  defp print_time({hours, minutes, seconds}) do
    IO.puts "#{stringify_time(hours)}:#{stringify_time(minutes)}:#{stringify_time(seconds)}"
  end

  defp stringify_time(time) when time >= 10, do: "#{time}"
  defp stringify_time(time), do: "0#{time}"

  defp update_seconds({hours, minutes, 59}), do: update_minutes({hours, minutes, 0})
  defp update_seconds({hours, minutes, seconds}), do: {hours, minutes, seconds + 1}

  defp update_minutes({hours, 59, seconds}), do: update_hours({hours, 0, seconds})
  defp update_minutes({hours, minutes, seconds}), do: {hours, minutes + 1, seconds}

  defp update_hours({12, minutes, seconds}), do: update_hours({1, minutes, seconds})
  defp update_hours({hours, minutes, seconds}), do: {hours + 1, minutes, seconds}
end

Clock.start()

clock.js

class Clock {
  constructor() {
    this.hours = 0;
    this.minutes = 0;
    this.seconds = 0;
  }

  static stringifyTime(timeUnit) {
    if (timeUnit >= 10) {
      return '' + timeUnit;
    }
    else {
      return '0' + timeUnit;
    }
  }

  start() {
    this.printTime();
    setTimeout(() => this.incrementTime(), 1000);
  }

  incrementTime() {
    this.updateSeconds();
    this.printTime();

    setTimeout(() => this.incrementTime(), 1000);
  }

  updateSeconds() {
    if (this.seconds === 59) {
      this.seconds = 0;
      this.updateMinutes();
    } else {
      this.seconds++;
    }
  }

  updateMinutes() {
    if (this.minutes === 59) {
      this.minutes = 0;
      this.updateHours();
    } else {
      this.minutes++;
    }
  }

  updateHours() {
    if (this.hours == 24) {
      this.hours = 1;
    } else {
      this.hours++;
    }
  }

  printTime() {
    const stringHours = Clock.stringifyTime(this.hours);
    const stringMinutes = Clock.stringifyTime(this.minutes);
    const stringSeconds = Clock.stringifyTime(this.seconds);

    console.log(stringHours + ':' + stringMinutes + ':' + stringSeconds);
  }
}

const clock = new Clock();

clock.start();

clock.rb

class Clock
  def initialize
    @hours = 12
    @minutes = 0
    @seconds = 0
  end

  def start
    print_time
    sleep 1
    increment_time
  end

  private

  def increment_time
    update_seconds
    print_time
    sleep 1
    increment_time
  end

  def stringify_time(time_unit)
    if time_unit >= 10
      "#{time_unit}"
    else
      "0#{time_unit}"
    end
  end

  def print_time
    string_hours = stringify_time(@hours)
    string_minutes = stringify_time(@minutes)
    string_seconds = stringify_time(@seconds)

    puts "#{string_hours}:#{string_minutes}:#{string_seconds}"
  end

  def update_seconds
    if @seconds == 59
      @seconds = 0
      update_minutes
    else
      @seconds += 1
    end
  end

  def update_minutes
    if @minutes == 59
      @minutes = 0
      update_hours
    else
      @minutes += 1
    end
  end

  def update_hours
    if @hours == 12
      @hours = 0
    else
      @hours += 1
    end
  end
end

clock = Clock.new
clock.start