Invert website lightness

Invert.js

function rgbToHsl([r, g, b]) {
	r /= 255, g /= 255, b /= 255;

	var max = Math.max(r, g, b), min = Math.min(r, g, b);
	var h, s, l = (max + min) / 2;

	if (max == min) {
		h = s = 0; // achromatic
	} else {
		var d = max - min;
		s = l > 0.5 ? d / (2 - max - min) : d / (max + min);

		switch (max) {
			case r:
				h = (g - b) / d + (g < b ? 6 : 0);
				break;
			case g:
				h = (b - r) / d + 2;
				break;
			case b:
				h = (r - g) / d + 4;
				break;
		}

		h /= 6;
	}

	return [h, s, l];
}

function hslToRgb([h, s, l]) {
	var r, g, b;

	if (s == 0) {
		r = g = b = l; // achromatic
	} else {
		function hue2rgb(p, q, t) {
			if (t < 0) t += 1;
			if (t > 1) t -= 1;
			if (t < 1 / 6) return p + (q - p) * 6 * t;
			if (t < 1 / 2) return q;
			if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
			return p;
		}

		var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
		var p = 2 * l - q;

		r = hue2rgb(p, q, h + 1 / 3);
		g = hue2rgb(p, q, h);
		b = hue2rgb(p, q, h - 1 / 3);
	}

	return [r * 255, g * 255, b * 255];
}

function convert(color) {
	color = rgbToHsl(color.map(c => Number(c)));
	const percent = color[1] > 0.3 ? '' : '%';
	color[2] = 1 - color[2];
	color = hslToRgb(color);
	return `rgb${color[3] ? 'a' : ''}(${Math.round(color[0])}${percent}, ${Math.round(color[1])}${percent}, ${Math.round(color[2])}${percent}${color[3] ? ',' + Math.round(color[3]) : ''})`;
}

function match(shr, p) {
	if (shr && shr.style && shr.style[p]) {
		let color = shr.style[p].match(/[0-9]*\.[0-9]+|[0-9]+/g);
		if (color) {
			const update = convert(color, shr, p);
			shr.style[p] = update;
		}
	}
}

function match_adv(shr, p) {
	if (shr.style[p]) {
		shr.style[p] = shr.style[p].replace(/rgba?\(.+?\)/g, c => {
			let color = c.match(/[0-9]*\.[0-9]+|[0-9]+/g);
			if (color) {
				return convert(color);
			}
		})
	}
}

const styles = {
	color: match,
	backgroundColor: match,
	backgroundImage: match_adv,
	borderBottomColor: match,
	borderBottom: match_adv,
	borderTopColor: match,
	borderTop: match_adv,
	borderLeftColor: match,
	borderLeft: match_adv,
	borderRightColor: match,
	borderRight: match_adv,
	borderColor: match,
	outlineColor: match,
	caretColor: match,
	columnRuleColor: match,
	textDecorationColor: match
};

Object.values(document.styleSheets).forEach(sh => {
		try {
			if (sh) Object.values(sh.cssRules).forEach(shr => {
				if (shr && shr.style) {
					Object.entries(styles).forEach(([p, func]) => {
						func(shr, p);
					})
				}
			})
		} catch (e) {
			console.log(e);
		}
	}
)