PrettierPartial formats the entire buffer in visual mode

Do you want to request a feature or report a bug?
This is possibly a bug... But it is likely I am not doing things correctly

What is the current/expected behavior?
When I do :PrettierPartial in visual mode, the entire buffer gets formatted (both the selected text and the unselected text), but when I do :Prettier or :PrettierAsync in visual mode, only the selected text is formatted. Is this the expected behavior? It seems to me their names suggest the reverse... Am I doing something wrong? I am happy to provide extra config info if this is an unexpected behavior.

What version of vim-prettier are you using - (output of :PrettierVersion) ?

:PrettierVersion
1.0.0-alpha

What version of prettier are you using - (output of :PrettierCliVersion) ?

:PrettierVersion
1.19.1

What is your prettier executable path - (output of :PrettierCliPath) ?

:PrettierCliPath
$HOME/.vim/bundle/vim-prettier/node_modules/.bin/prettier

Did this work in previous versions of vim-prettier and/or prettier ?
Haven't tried

Reproduce the reported behavior by selecting text in visual mode and running :PrettierPartial, then compare it with :Prettier and :PrettierAsync. Determine the intended selection scope and consider the issue resolved when the commands' behavior matches their documented or intended semantics.