Timer

⏳ A small and smooth (60-fps) countdown timer and stopwatch for Vue and vanilla JS.

This project is part of #CreateWeekly, my attempt to create something new publicly every week in 2020.

Demo

https://timerlib.netlify.app

Installation

npm install @josephuspaye/timer --save

Usage

JS

The following creates a 15-second countdown timer without a user interface:

import { Timer } from '@josephuspaye/timer';

const timer = new Timer('countdown', 10 * 1000); // change 'countdown' to 'stopwatch' for a stopwatch

timer.on('tick', (ms) => {
    console.log('event: tick', ms);
});
timer.on('done', () => {
    console.log('event: done');
});
timer.on('state', (state) => {
    console.log('event: state', state);
});

timer.start();

Vue: default template

You can create a timer with the default template, which shows days, hours, minutes, seconds, and milliseconds. You can also use the following classes to style the resulting timer:

• timer - added to the timer root element (a div element). is-done is appended when the timer reaches its length, and is-overflowed is appended when it exceeds its length.
• timer__delimiter - added to the : delimiters (span elements)
• timer__days - added to the timer days (a span element)
• timer__hours - added to the timer hours (a span element)
• timer__seconds - added to the timer seconds (a span element)
• timer__milliseconds - added to the timer milliseconds (a span element)

The following creates a simple 15-second countdown timer that starts automatically (view on CodePen):

<template>
    <div>
        <Timer type="countdown" autoStart :length="15 * 1000" />
        <!-- change the above to `type="stopwatch"` for a stopwatch -->
    </div>
</template>

<script>
import { TimerVue as Timer } from '@josephuspaye/timer';

export default {
    components: { Timer },
};
</script>

Vue: custom template

You can use a scoped slot to render your own template.

The following renders a custom template with 15-second stopwatch that starts automatically and allows for overflow (view on CodePen):

<template>
    <div>
        <Timer
            type="stopwatch"
            auto-start
            allow-overflow
            :length="15 * 1000"
            v-slot="{ time, isDone, isOverflowed }"
        >
            <!-- change the above to `type="countdown"` for a countdown timer -->
            <div>
                <span :class="{ 'is-overflowed': isOverflowed }">
                    <span>{{ time.d }}d</span>
                    <span>{{ time.h }}h</span>
                    <span>{{ time.m }}m</span>
                    <span>{{ time.s }}s</span>
                    <span>{{ time.ms }}ms</span>
                </span>

                <span>{{ isDone ? '✅' : '⏳' }}</span>
            </div>
        </Timer>
    </div>
</template>

<script>
import { TimerVue as Timer } from '@josephuspaye/timer';

export default {
    components: { Timer },
};
</script>

<style>
.is-overflowed {
    color: red;
}
</style>

JS API

The Timer class can be used to create a timer without a user interface.

Properties and methods

Create a timer using const timer = new Timer(type, options) and call methods using timer.method().

/**
 * The type of timer: 'countdown' or 'stopwatch'
 */
export declare type TimerType = 'countdown' | 'stopwatch';

/**
 * The timer state, one of 'stopped', 'running', 'paused'
 */
export declare type TimerState = 'stopped' | 'running' | 'paused';

/**
 * Timer constructor options
 */
export interface TimerOptions {
    /**
     * Whether the timer should allow overflow. If true, the timer will
     * set `isOverflowed` and continue counting when the length is
     * reached. Otherwise, the timer stops upon reaching the length.
     */
    allowOverflow?: boolean;
}

export declare class Timer {
    /**
     * The type of timer: 'countdown' or 'stopwatch'
     */
    type: TimerType;

    /**
     * The timer state, one of 'stopped', 'running', 'paused'
     */
    state: TimerState;

    /**
     * Indicates whether the timer allows overflow. When true, the timer
     * will set `isOverflowed` and continue counting when the length is
     * reached. Otherwise, the timer stops upon reaching the length.
     */
    allowOverflow: boolean;

    /**
     * Indicates whether the timer has overflowed (i.e. exceeded the length)
     */
    isOverflowed: boolean;

    /**
     * Indicates whether the timer is done (i.e. met or exceeded the length)
     */
    isDone: boolean;

    /**
     * The timer event emitter
     */
    events: Emitter;

    /**
     * Create a new timer
     *
     * @param type    The type of timer: 'countdown' or 'stopwatch'
     * @param length  How long the timer should count down from or count up to
     * @param options The timer options
     */
    constructor(type: TimerType, length: number, options?: TimerOptions);

    /**
     * The elapsed time in milliseconds. Is zero if the timer is stopped.
     */
    get time(): number;

    /**
     * Set the timer's length. Will stop the timer and reset internal state for a new run.
     */
    setLength(length: number): void;

    /**
     * Reset the timer
     */
    reset(): void;

    /**
     * Start the timer
     */
    start(): void;

    /**
     * Stop the timer
     */
    stop(options?: { isDone: boolean }): void;

    /**
     * Pause the timer
     */
    pause(): void;

    /**
     * Resume the timer
     */
    resume(): void;

    /**
     * Destroy the timer and event listeners
     */
    destroy(): void;
}

Events

Listen for any of the following timer events using timer.events.on('event', callbackFunction):

Event	Description
state	Emitted when the timer state changes. The handler is called with the new state, one of stopped, running or paused.
overflow	Emitted when the timer exceeds its length.
done	Emitted when the timer reaches its length.
tick	Emitted when the timer advances. The handler is called with the total time elapsed, in milliseconds. When the timer is running, this is emitted 60 times a second.
reset	Emitted when the timer is reset. The handler is called with the time it was reset to, in milliseconds.
start	Emitted when the timer is started.
stop	Emitted when the timer is stopped.
pause	Emitted when the timer is paused.
resume	Emitted when the timer is resumed.

Vue API

Props

Prop	Type	Default	Description
type	String	countdown	The type of timer. One of countdown or stopwatch. This value can be changed while the timer is running.
length	Number		How long the timer is running for, in milliseconds. Changing this while the timer is running will cause it to stop and reset.
autoStart	Boolean	false	When true, the timer will start automatically on mount. Otherwise the start() method has to be called to start it.
allowOverflow	Boolean	false	When true, the timer will continue when its length is exceeded. Otherwise it will stop upon reaching its length.

Methods

Event	Description
start()	Start the timer.
stop()	Stop the timer.
pause()	Pause the timer if it's running.
resume()	Resume the timer if it's paused.
toggle()	Toggle the timer. Will start the timer if stopped, pause if running, and resume if paused.
reset()	Stop and reset the timer, for a possible restart.

Events

Event	Description
state	Emitted when the timer state changes. The handler is called with the new state, one of stopped, running or paused.
overflow	Emitted when the timer exceeds its length.
done	Emitted when the timer reaches its length.
tick	Emitted when the timer advances. The handler is called with the total time elapsed, in milliseconds. When the timer is running, this is emitted 60 times a second.
reset	Emitted when the timer is reset. The handler is called with the time it was reset to, in milliseconds.
start	Emitted when the timer is started.
stop	Emitted when the timer is stopped.
pause	Emitted when the timer is paused.
resume	Emitted when the timer is resumed.

Slots

Slot	Description
(default)	The default slot. Can hold any content with a single root element, and is passed the props listed below.

Default slot props

Prop	Type	Description
time	Object	The timer's current time as an object with keys d (days), h (hours), m (minutes), s (seconds), and ms (milliseconds). Each value is a padded string ready for display.
timeElapsed	Number	For a countdown, the total time remaining, in milliseconds. For a stopwatch, the total time elapsed, in milliseconds.
state	String	The timer's current state, one of stopped, running or paused.
isDone	Boolean	Whether or not the timer has reached its length.
isOverflowed	Boolean	Whether or not the timer has exceeded its length.

Licence

MIT