The wave quality of light is the same as that of the electron. The wave is the mathematics that determines the probable location of the photon of light when it is detected. The wave character of light is not a wave of vibrating stuff like a water wave but a wavelike function encoding information about where you’ll find the photon of light once it is detected. Until it reaches the detector plate, like the electron, it is seemingly passing through both slits simultaneously, making its mind up about its location in space only once it is observed.
