Purpose of brown sugar in chocolate chip cookies?

* Adds moisture. Brown sugar contains molasses, which is a natural humectant, meaning that it attracts and retains water. This helps to keep cookies moist and chewy.

* Provides a richer flavor. Brown sugar has a more complex flavor than white sugar, due to the presence of molasses. This can give chocolate chip cookies a deeper, more nuanced flavor.

* Creates a chewier texture. Brown sugar also contains a small amount of fiber, which can help to create a chewier texture in cookies.

* Improves browning. Brown sugar can help to create a more golden brown color in cookies, due to the presence of molasses.