Mimic Illustrator gradient editor stop behavior

In Illustrator, clicking on a gradient adds a stop with the exact color value where the gradient was clicked. This UX pattern makes sense, rather than the Photoshop/After Effects pattern whereby it adds one of the existing stops again where the gradient is clicked (which stop? The one to the left of the cursor for some reason!). Illustrator's solution is super helpful to find exact values at any point along the gradient, as well as creating a very specific "ease" to the gradient colors.