A timer to detect lapses in browser activity

The initial implementation is based on jquery-idletimer, but rewritten to break the dependency on jQuery, and to take advantage of modern JavaScript.

The browser is considered "idle", if within a specified period of time:

• The mouse has not moved
• The mouse wheel has not scrolled
• No key has been pressed

When such an "idle" state is detected, an event is dispatched on the element on which the idle timer has been registered.

import IdleTimer from 'idle-timer';

let handle_idle_timer_event = function(event) {
    const detail = event.detail;
    const timer = detail.timer;
    const original_event = detail.event; /* N.B. May be null */
    console.log('timer: %s (%s)',
                event.type,
                (original_event ? original_event.type : null));
};

console.log('timer: setup');
let timer = new IdleTimer({timeout: 2000, element: window.document});
window.document.addEventListener('idle-timer:idle', handle_idle_timer_event);
window.document.addEventListener('idle-timer:active', handle_idle_timer_event);

Defaulting to document, this indicates the element which is to be monitored for activity.

Defaulting to false, this indicates whether the instance should be considered "idle" initially.

Defaulting to 30000, this indicates the duration in milliseconds after which the "idle" state is triggered.

This indicates the array of events to be monitored, and defaults to the following value.

[
    'mousemove',
    'keydown',
    'wheel',
    'DOMMouseScroll',
    'mousewheel',
    'mousedown'
]

Defaulting to null, this indicates a localStorage key to be used for synchronising the timer between multiple browser tabs/windows.

Clean up a timer that is no longer required:

timer.destroy();

Reset a timer to its initial conditions:

timer.reset();

Pause a timer:

timer.pause();

Resume a previously-paused timer:

timer.resume();

Get the number of milliseconds remaining until "idle" state detected by timer:

timer.get_remaining_time();

Get the number of milliseconds elapsed on timer since the last "idle" or "active" state transition occurred:

timer.get_elapsed_time();

Get the timestamp in milliseconds of the last detected activity:

timer.get_last_active_time();

Is timer currently indicating an "idle" state?

timer.is_idle();