Different color spaces have different numbers of components.
For example RGB color spaces have three components and CMYK
color spaces have four.
This property allows you to determine the number of color
components in the color space.
Indexed color spaces define colors via a palette. So although a
color value is determined via a single index into a palette, the
number of components is determined by the number of color
components in the palette.
For example the number of components in an indexed RGB color
space is three.
Pattern color spaces are special and have no components.