R code visualization with flowchart

Question

Are there any tools that can visualize R code?

I have a very complex R code, split between several scripts that I need to understand. Part of the difficulty is that there are so many nested functions and variables that it very slowly goes through it manually and finds out what is connected with what.

I think my task could be simpler if there is some way to generate a flowchart from R code so that I can see everything at once. Of course, I can just draw a map when I look through the code, but can't it be programmatically possible? Are there any existing tools that can do this?

I found a program called R AnalyticFlow, but it seems to be creating scripts using a GUI, while I want something that can take code and turn it into a type of thing that could be used in AnalyticFlow.