What

Fire an event on a trackpad or mousewheel flick. Scroll values on trackpads can have inertia and take a long time to come back down to 0 - this plugin smooths out those false positive scroll events. Demo

How

HTML:

<script src="path/to/onFlick"></script>

JS:

new OnFlick( callback, options );

Parameters:

• callback - Function to run when flick event is triggered. Accepts the mousewheel event as an argument.
• options - Optional object. Outlined below.

Options

{
    debounce: 600, // How long, in ms, to wait after the callback is invoked before it can be invoked again
    threshold: 10 // How fast the user needs to be scrolling in order to trigger the callback. Accepts a number referring to the average scroll delta necessary to trigger the event.
});

How it works

The plugin keeps a running tally of the last 10 scroll deltas. Each frame that the mousewheel event is called, it:

• trims the oldest delta value if necessary
• saves the latest delta value
• averages them together
• tests if the average is above the threshold defined in the options.

This is more effective than a debounce function because debounce limits the frequency of a callback, not the conditions for triggering that callback. OnFlick combines the hard time limit of a debounce with an effort to make sure the user is actively moving on the page, not just running off of the inertia of an old trackpad event.

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Version 2.0