Timer

Charming::Components::Timer is a countdown clock. It renders the remaining time as mm:ss (or h:mm:ss once an hour is involved) and clamps at zero. It is a static renderable — call tick from a controller timer firing once per second, check expired?, and re-render.

04:32 remaining

Quick start

Controllers are rebuilt per dispatch, so track elapsed seconds in state and rebuild the countdown from it:

class PomodoroState < ApplicationState
  attribute :elapsed, :integer, default: 0
end

class PomodoroController < ApplicationController
  DURATION = 25 * 60

  timer :countdown, every: 1, action: :advance

  def show
    render :show, countdown: countdown
  end

  def advance
    pomodoro.elapsed += 1
    return navigate_to("/break") if countdown.expired?

    show
  end

  private

  def countdown
    @countdown ||= Charming::Components::Timer.new(duration: DURATION, label: "remaining")
      .tick(pomodoro.elapsed)
  end

  def pomodoro
    state(:pomodoro, PomodoroState)
  end
end

<%= render_component countdown %>

Options

Option	Default	What it does
duration:	required	Countdown length in whole seconds. Negative values clamp to 0.
label:	nil	Text appended after the clock.
theme:	nil	Theme passed through to the component base class.

Working with it

• tick(seconds = 1) — counts down by seconds, clamping at zero. Returns self.
• expired? — true once remaining hits zero.
• reset — restores the full duration. Returns self.
• remaining / duration / label — readers.

Tips

• Fractional ticks accumulate: a controller timer firing at every: 0.25 can call tick(0.25) and four ticks advance the clock one second. The display still shows whole seconds (TimeDisplay.clock floors).
• duration: is truncated to an integer — duration: 90.5 becomes 90 seconds.
• The renderable holds no wall-clock reference; it only knows what you tick into it. If your timer pauses (for example while the terminal is unfocused), the countdown pauses too.