In built way to automatically Darken or Lighten by amount depending on the color luminance

[Bruno]

I want to change automatically choose the background color of a button when pressed. It shall darken the color if it is light, and lighten it if it's dark, and I think tinyColor could have this function.

It could just check the luminance/brightness of the color (like the L component of HSL) , and depending on it, darken() or lighten() by an amount.

It could be like

darkenLighten(color: Color, amount: number = x, threshold: number = y)

Amount is how much it should change the L, threshold is how much L, from 0 to 100, it should choose to use darken or lighten.

Throwing out numbers without any test, x could be like 10, threshold maybe 50.