Function parseCssColor

packages/cli/src/linter/model/color-parser.ts:62–255

(colorStr: string)

 * Returns null if the color is invalid.
 */
export function parseCssColor(colorStr: string): ParsedColorResult | null {
  if (typeof colorStr !== 'string') return null;
  const clean = colorStr.trim().toLowerCase();
  if (!clean) return null;

  // 1. Hex Color Pattern
  if (clean.startsWith('#')) {
    if (!/^#([0-9a-f]{3,4}|[0-9a-f]{6}|[0-9a-f]{8})$/.test(clean)) {
      return null;
    }
    return parseHex(clean);
  }

  // 2. Named Colors lookup
  if (Object.prototype.hasOwnProperty.call(CSS_NAMED_COLORS, clean)) {
    return parseHex(CSS_NAMED_COLORS[clean]!);
  }

  // 3. Functional notations parse
  const parsedFunc = tokenizeFunc(clean);
  if (!parsedFunc) {
    return null;
  }

  const { name, args } = parsedFunc;

  switch (name) {
    case 'rgb':
    case 'rgba': {
      // Supports rgb(255, 0, 0) and rgb(255 0 0 / 0.5)
      // args could be: [r, g, b] or [r, g, b, a]
      if (args.length !== 3 && args.length !== 4) return null;
      const rRaw = parsePercentOrNumber(args[0]!, 255);
      const gRaw = parsePercentOrNumber(args[1]!, 255);
      const bRaw = parsePercentOrNumber(args[2]!, 255);
      const aVal = args.length === 4 ? parseAlpha(args[3]) : 1;

      if (isNaN(rRaw) || isNaN(gRaw) || isNaN(bRaw) || isNaN(aVal)) return null;

      const r = Math.max(0, Math.min(255, Math.round(rRaw)));
      const g = Math.max(0, Math.min(255, Math.round(gRaw)));
      const b = Math.max(0, Math.min(255, Math.round(bRaw)));
      const a = Math.max(0, Math.min(1, aVal));

      return makeResult(r, g, b, a);
    }
    case 'hsl':
    case 'hsla': {
      // Supports hsl(120, 100%, 50%) and hsl(120deg 100% 50% / 0.5)
      if (args.length !== 3 && args.length !== 4) return null;
      const h = parseHue(args[0]!);
      const s = parsePercentOrNumber(args[1]!, 1);
      const l = parsePercentOrNumber(args[2]!, 1);
      const a = args.length === 4 ? parseAlpha(args[3]) : 1;

      if (isNaN(h) || isNaN(s) || isNaN(l) || isNaN(a)) return null;

      const rgb = hslToRgb(h, s, l);