Consistently handle none/NaN across library

src/contrast/APCA.js

@@ -4,6 +4,7 @@
 
 import getColor from "../getColor.js";
 import to from "../to.js";
+import {isNone} from "../util.js";
 
 // exponents
 const normBG = 0.56;
@@ -54,11 +55,15 @@ export default function contrastAPCA (background, foreground) {
 
 	// Calculates "screen luminance" with non-standard simple gamma EOTF
 	// weights should be from CSS Color 4, not the ones here which are via Myndex and copied from Lindbloom
-	[R, G, B] = foreground.coords;
+	[R, G, B] = foreground.coords.map(c => {
+		return isNone(c) ? 0 : c;
+	});
 	let lumTxt = linearize(R) * 0.2126729 + linearize(G) * 0.7151522 + linearize(B) * 0.0721750;
 
 	background = to(background, "srgb");
-	[R, G, B] = background.coords;
+	[R, G, B] = background.coords.map(c => {
+		return isNone(c) ? 0 : c;
+	});
 	let lumBg = linearize(R) * 0.2126729 + linearize(G) * 0.7151522 + linearize(B) * 0.0721750;
 
 	// toe clamping of very dark values to account for flare

src/deltaE/deltaECMC.js

@@ -1,6 +1,7 @@
 import lab from "../spaces/lab.js";
 import lch from "../spaces/lch.js";
 import getColor from "../getColor.js";
+import {isNone} from "../util.js";
 
 // More accurate color-difference formulae
 // than the simple 1976 Euclidean distance in Lab
@@ -87,7 +88,7 @@ export default function (color, sample, {l = 2, c = 1} = {}) {
 
 	// Cross term T for blue non-linearity
 	let T;
-	if (Number.isNaN(H1)) {
+	if (isNone(H1)) {
 		H1 = 0;
 	}
 

src/deltaE/deltaEJz.js

@@ -1,5 +1,6 @@
 import jzczhz from "../spaces/jzczhz.js";
 import getColor from "../getColor.js";
+import {isNone} from "../util.js";
 
 // More accurate color-difference formulae
 // than the simple 1976 Euclidean distance in Lab
@@ -23,16 +24,16 @@ export default function (color, sample) {
 	let ΔC = Cz1 - Cz2;
 
 	// length of chord for ΔH
-	if ((Number.isNaN(Hz1)) && (Number.isNaN(Hz2))) {
+	if ((isNone(Hz1)) && (isNone(Hz2))) {
 		// both undefined hues
 		Hz1 = 0;
 		Hz2 = 0;
 	}
-	else if (Number.isNaN(Hz1)) {
+	else if (isNone(Hz1)) {
 		// one undefined, set to the defined hue
 		Hz1 = Hz2;
 	}
-	else if (Number.isNaN(Hz2)) {
+	else if (isNone(Hz2)) {
 		Hz2 = Hz1;
 	}
 

src/distance.js

@@ -1,4 +1,5 @@
 import ColorSpace from "./space.js";
+import {isNone} from "./util.js";
 
 /**
  * Euclidean distance of colors in an arbitrary color space
@@ -12,7 +13,7 @@ export default function distance (color1, color2, space = "lab") {
 
 	return Math.sqrt(coords1.reduce((acc, c1, i) => {
 		let c2 = coords2[i];
-		if (isNaN(c1) || isNaN(c2)) {
+		if (isNone(c1) || isNone(c2)) {
 			return acc;
 		}
 

src/interpolation.js

@@ -2,7 +2,7 @@
  * Functions related to color interpolation
  */
 import ColorSpace from "./space.js";
-import {type, interpolate} from "./util.js";
+import {type, interpolate, isNone} from "./util.js";
 import getColor from "./getColor.js";
 import clone from "./clone.js";
 import to from "./to.js";
@@ -167,10 +167,10 @@ export function range (color1, color2, options = {}) {
 		// Undefined hues must be evaluated before hue fix-up to properly
 		// calculate hue arcs between undefined and defined hues.
 		// See https://github.com/w3c/csswg-drafts/issues/9436#issuecomment-1746957545
-		if (isNaN(θ1) && !isNaN(θ2)) {
+		if (isNone(θ1) && !isNone(θ2)) {
 			θ1 = θ2;
 		}
-		else if (isNaN(θ2) && !isNaN(θ1)) {
+		else if (isNone(θ2) && !isNone(θ1)) {
 			θ2 = θ1;
 		}
 		[θ1, θ2] = angles.adjust(arc, [θ1, θ2]);

src/space.js

@@ -1,4 +1,4 @@
-import {type, parseCoordGrammar, serializeNumber, mapRange} from "./util.js";
+import {type, parseCoordGrammar, serializeNumber, mapRange, isNone} from "./util.js";
 import {getWhite} from "./adapt.js";
 import hooks from "./hooks.js";
 import getColor from "./getColor.js";
@@ -103,7 +103,7 @@ export default class ColorSpace {
 			let meta = coordMeta[i];
 
 			if (meta.type !== "angle" && meta.range) {
-				if (Number.isNaN(c)) {
+				if (isNone(c)) {
 					// NaN is always in gamut
 					return true;
 				}
@@ -186,7 +186,7 @@ export default class ColorSpace {
 		}
 
 		// Convert NaN to 0, which seems to be valid in every coordinate of every color space
-		coords = coords.map(c => Number.isNaN(c) ? 0 : c);
+		coords = coords.map(c => isNone(c) ? 0 : c);
 
 		// Find connection space = lowest common ancestor in the base tree
 		let myPath = this.path;

src/spaces/lch.js

@@ -1,6 +1,7 @@
 import ColorSpace from "../space.js";
 import Lab from "./lab.js";
 import {constrain as constrainAngle} from "../angles.js";
+import {isNone} from "../util.js";
 
 export default new ColorSpace({
 	id: "lch",
@@ -49,7 +50,7 @@ export default new ColorSpace({
 			Chroma = 0;
 		}
 		// Deal with NaN Hue
-		if (isNaN(Hue)) {
+		if (isNone(Hue)) {
 			Hue = 0;
 		}
 		return [

src/spaces/lchuv.js

@@ -1,6 +1,7 @@
 import ColorSpace from "../space.js";
 import Luv from "./luv.js";
 import {constrain as constrainAngle} from "../angles.js";
+import {isNone} from "../util.js";
 
 export default new ColorSpace({
 	id: "lchuv",
@@ -49,7 +50,7 @@ export default new ColorSpace({
 			Chroma = 0;
 		}
 		// Deal with NaN Hue
-		if (isNaN(Hue)) {
+		if (isNone(Hue)) {
 			Hue = 0;
 		}
 		return [

src/spaces/oklch.js

@@ -1,6 +1,7 @@
 import ColorSpace from "../space.js";
 import OKLab from "./oklab.js";
 import {constrain as constrainAngle} from "../angles.js";
+import {isNone} from "../util.js";
 
 export default new ColorSpace({
 	id: "oklch",
@@ -48,7 +49,7 @@ export default new ColorSpace({
 		let a, b;
 
 		// check for NaN hue
-		if (isNaN(h)) {
+		if (isNone(h)) {
 			a = 0;
 			b = 0;
 		}