How to use the @elastic/eui.isColorDark function in @elastic/eui

_needsLightText(bgColor) {
    const color = /rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(bgColor);
    if (!color) {
      return false;
    }
    return isColorDark(parseInt(color[1]), parseInt(color[2]), parseInt(color[3]));
  }

_needsLightText(bgColor) {
    const color = /rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(bgColor);
    if (!color) {
      return false;
    }
    return isColorDark(parseInt(color[1]), parseInt(color[2]), parseInt(color[3]));
  }

}}
                className="gphNode"
              >

_needsLightText(bgColor) {
    const color = /rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(bgColor);
    if (!color) {
      return false;
    }
    return isColorDark(parseInt(color[1]), parseInt(color[2]), parseInt(color[3]));
  }

labelColor = d => {
          const bgColor = z(d);
          const color = /rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(bgColor);
          return color && isColorDark(parseInt(color[1]), parseInt(color[2]), parseInt(color[3]))
            ? '#FFF' : '#222';
        };
      }

<div>
        {text &amp;&amp; (
          <span>
            {text}
            &nbsp;
          </span>
        )}
        
      </div>
    );
  }

  const rgb = hexToRgb(backgroundColor);
  let color = 'text';

  if (rgb &amp;&amp; isColorDark(rgb[0], rgb[1], rgb[2])) {
    color = 'ghost';
  }

  return (
    <div>
      {text &amp;&amp; (
        <span>
          {text}
          &nbsp;
        </span>
      )}
      
    </div>
  );
};

labelColor = d => {
            const bgColor = z(d);
            const color = /rgb\(\s*(\d+)\s*,\s*(\d+)\s*,\s*(\d+)\s*\)/.exec(bgColor);
            return color && isColorDark(parseInt(color[1]), parseInt(color[2]), parseInt(color[3]))
              ? '#FFF' : '#222';
          };
        }