Method parseColorGroup

src/Parser.ts:678–702

* Parses a color description.

(optional: boolean)

     * Parses a color description.
     */
    parseColorGroup(optional: boolean): ParseNode<"color-token"> | null {
        const res = this.parseStringGroup(optional);
        if (res == null) {
            return null;
        }
        const match = (
            /^(#[a-f0-9]{3,4}|#[a-f0-9]{6}|#[a-f0-9]{8}|[a-f0-9]{6}|[a-z]+)$/i
        ).exec(res.text);
        if (!match) {
            throw new ParseError("Invalid color: '" + res.text + "'", res);
        }
        let color = match[0];
        if (/^[0-9a-f]{6}$/i.test(color)) {
            // We allow a 6-digit HTML color spec without a leading "#".
            // This follows the xcolor package's HTML color model.
            // Predefined color names are all missed by this RegEx pattern.
            color = "#" + color;
        }

        return {
            type: "color-token",
            mode: this.mode,
            color,
        };
    }

    /**
     * Parses a size specification, consisting of magnitude and unit.