How to check if hex color is “too black”?

Question

I\'m trying to evaluate the darkness of a color chosen by a color picker to see if it\'s \"too black\", and if so, set it to white. I thought I could use the first character

Answer 1

I found this WooCommerce Wordpress PHP function (wc_hex_is_light) and I converted to JavaScript. Works fine!

function wc_hex_is_light(color) {
    const hex = color.replace('#', '');
    const c_r = parseInt(hex.substr(0, 2), 16);
    const c_g = parseInt(hex.substr(2, 2), 16);
    const c_b = parseInt(hex.substr(4, 2), 16);
    const brightness = ((c_r * 299) + (c_g * 587) + (c_b * 114)) / 1000;
    return brightness > 155;
}