Selecting a Javascript arrow function in Vim - vim

Question

It's been a challenge for me to select a whole arrow function via Vim without using relative line numbers. Any thoughts on how I can accomplish that?
Here is an example:
const myFunction = () => {
console.log('hello')
}

Answer 1

As always in Vim, there are lots of ways to do that but the right way is very context-dependent. For example, this problem:
const myFunction = () => {
console.log('hello')
}
is different from this problem:
console.log('---')
const myFunction = () => {
console.log('hello')
}
console.log('---')
or this one:
console.log('---')
const myFunction = () => {
console.log('hello')
}
console.log('---')
and the location of the cursor might be important as well.
Assuming your cursor is somewhere on the first or last line of the snippet, the following command should do what you want:
$V% " move cursor to end of line,
" enter visual-line mode,
" extend the selection to the matching pair
If the cursor is somewhere in the body, you could simply do Vip to visually select the current paragraph but that won't work if there are empty lines in the body or if you have other lines above and below. This is why context matters.
With the cursor somewhere in the body, you could do:
[mV% " jump to previous start of method,
" enter visual-line mode,
" extend the selection to the matching pair
But there are various ways in which it might not work, like when you are in a conditional or a switch.
FWIW, I have used (and updated) the following snippet for many years because the built-in ways have always felt limited to me:
" in after/ftplugin/javascript.vim
function! SelectFunction() abort
call search('\(function\|=>\)', "bWc")
call search("{", "Wc")
normal v%V
endfunction
xnoremap <buffer> af :<C-u>call SelectFunction()<CR>
onoremap <buffer> af :normal vaf<CR>
SelectFunction() searches for a typical JS function declaration at or before the cursor, then it searches for the opening brace at or after the cursor, then it visually selects until the matched pair.
The two mappings essentially define a custom pseudo-text object af that uses SelectFunction() under the hood. It is not a real text object in the sense that it doesn't support count or nesting, but it is nevertheless pretty damn useful:
vaf " visually select current function
daf " cut current function
yaf " yank current function
" etc.
vaf with the cursor somewhere in the body, then daf with the cursor on the closing brace:
Note that the function above probably has shortcomings. From previous interactions with the community, it seems that "select the current function" is not exactly a solved problem.