4nm/dist/colors/rgb.js

TypeScript reimplementation of Telegram's official library for communicating with Telegram Web Apps.

/**
 * Return true in case, passed value is RGBColor.
 * @param value - value to check.
 */
export function isRGB(value) {
    return /^#[\da-f]{3}$/i.test(value);
}
/**
 * Return true in case, passed value is RGBExtColor.
 * @param value - value to check.
 */
export function isRGBExt(value) {
    return /^#[\da-f]{6}$/i.test(value);
}
/**
 * Converts passed value to #RRGGBB format.
 * @param value - value to convert.
 * @throws {SyntaxError} Passed value does not contain any of known RGB formats.
 * @see isRGBExt
 * @see isRGB
 */
export function toRGBExt(value) {
    // Remove all spaces.
    const clean = value.replace(/\s/g, '');
    // Color is already in required format:
    // #RRGGBB
    if (isRGBExt(clean)) {
        return clean;
    }
    // Convert RGB to RRGGBB:
    // #RGB
    if (isRGB(clean)) {
        let color = '#';
        for (let i = 0; i < 3; i++) {
            color += clean[1 + i].repeat(2);
        }
        return color;
    }
    // Check if it is RGBCSSColor:
    // rgb(0,3,10)
    let match = clean.match(/^rgb\((\d{1,3}),(\d{1,3}),(\d{1,3})\)$/);
    // No matches, replace current match with another pattern.
    // rgba(32,114,8,0)
    if (match === null) {
        match = clean.match(/^rgba\((\d{1,3}),(\d{1,3}),(\d{1,3}),\d{1,3}\)$/);
    }
    // In case, this didn't work as well, we can't extract RGB color from passed
    // text.
    if (match === null) {
        throw new SyntaxError(`Value "${value}" does not match any of known RGB formats.`);
    }
    // Otherwise, take R, G and B components, convert to hex and create #RGB
    // string.
    return match.slice(1).reduce((acc, component) => {
        const formatted = parseInt(component).toString(16);
        return acc + (formatted.length === 1 ? '0' : '') + formatted;
    }, '#');
}