Why does this Plug search from the beginning of the line?

Question

I'm trying to use vim-repeat with a <Plug> that camel cases text:

nnoremap <silent> <Plug>CamelCase _ f_x~
\:call repeat#set("\<Plug>CamelCase")<CR>
nmap _ <Plug>CamelCase

This works fine for the most part, but in some cases it jumps to the beginning of the text and updates there:

function _noResponsesMessage(status_group) {

Even if I have my cursor at the beginning of status_group, it jumps to the beginning of the text and swaps there instead:

function NoResponsesMessage(status_group) {

Oddly, if I don't do this <Plug> setup and instead nmap it directly it works as expected:

nmap _ f_x~

Result as desired:

function _noResponsesMessage(statusGroup) {

Why does the first approach jump to the beginning of the line and the other replaces after the cursor?

Answer 1

If you look closely to your Plug:

nnoremap <silent> <Plug>CamelCase _ f_x~

You will notice that it consists of following normal mode commands:

1. _ goto first non-blank char on the line
2. goto next char
3. and then your camelcase solution f_x~

Just remove it to match your nmap solution:

nnoremap <silent> <Plug>CamelCase f_x~
nmap _ <Plug>CamelCase

I would also suggest to name Plugs in using ():

nnoremap <silent> <Plug>(CamelCase) f_x~
nmap _ <Plug>(CamelCase)

or ;

nnoremap <silent> <Plug>CamelCase; f_x~
nmap _ <Plug>CamelCase;

Just to avoid plug name clashes.