You can browse files in a directory through Vim using netrw. This can be done by editing a directory with Vim:
$vimsrc/
You'll see a listing of the files and directories in src:
app/
index.js
README.md
utils/
You can move your cursor over one of those files and hit R to rename it. A prompt will appear at the bottom of your Vim session with the file's current name spelled out. You can edit inline and then hit enter to apply the renaming.