Plucky: a standing wave underline

A little zero-dependency Web Component for the standing wave underline I'm using for the hover effect on the main nav of my personal website.

A demo is on the project description page, and the original details are described in a blog post.

Installation

This isn't on NPM because who else would want something so oddly specific? If you really want it, download Plucky.js and add it to your project.

Basic usage

Import the script and wrap any content you want in the custom element.

import { Plucky } from "/path/to/Plucky.js";

<plucky-underline>Some text</plucky-underline>

When using it for a hover effect on a link, put this component inside the link rather than outside. This is because the component defaults to coloring the underline with currentcolor, which is your link color when inside the link, but the default text color when outside.

<a href="example.html"><plucky-underline>Example</plucky-underline></a>

Styling

Basic styling is done with CSS custom properties:

• --plucky-line-color: color of the underline. Default: currentcolor
• --plucky-line-thickness: the thickness of the line. Default: max(.053em, 1px)
• --plucky-block-offset: shifts the null line up or down. Useful if it needs to be tweaked for a particular font or a weird baseline. Default: 0

For more advanced styling, it exposes two parts:

• line-path: styles the SVG path. E.g., plucky-underline::part(line-path) { stroke-dasharray: 3; }
• line-svg: styles the SVG element itself. This is really only exposed for applying CSS filters. E.g., plucky-underline::part(line-svg) { filter: drop-shadow(0 0 4px currentcolor); }

Options

You can control the wave itself with several options:

• Attribute amplitude / property amplitude: maximum amplitude when pulled (em). Default: .3
• Attribute num-half-waves / property numHalfWaves: the number of half-waves across the length of the element. Default: 4
• Attribute pull-duration / property pullDuration: duration of the "pull" (mouseover) effect (ms). Default: 120
• Attribute release-duration / property releaseDuration: duration of the "release" (mouseout) effect (ms). Default: 3500
• Attribute decay-freq / property decayFreq: how many cycles before fully damped. Default: 8

Known issues

This won't work if the underline wraps across multiple lines, so probably shouldn't be used for inline text.