system() by System.Job

test.vim

let s:Job = vital#vital#import('System.Job')

function! s:_on_stdout(data) abort dict
  let self.stdout[-1] .= a:data[0]
  call extend(self.stdout, a:data[1:])
endfunction

function! s:_on_stderr(data) abort dict
  let self.stderr[-1] .= a:data[0]
  call extend(self.stderr, a:data[1:])
endfunction

function! s:system(...) abort
  let job = s:Job.start(a:000, {
        \ 'stdout': [''],
        \ 'stderr': [''],
        \ 'on_stdout': function('s:_on_stdout'),
        \ 'on_stderr': function('s:_on_stderr'),
        \})
  let exit_status = job.wait()
  return {
        \ 'exit_status': exit_status,
        \ 'stdout': job.stdout,
        \ 'stderr': job.stderr,
        \}
endfunction


echo s:system('true')
echo s:system('false')
echo s:system('git', '-h')

{'stderr': [''], 'exit_status': 0, 'stdout': ['']}
{'stderr': [''], 'exit_status': 1, 'stdout': ['']}
{'stderr': ['Unknown option: -h', 'usage: git [--version] [--help] [-C <path>] [-c name=value]', '           [--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]', '           [-p | --paginate | --no-pager] [--no-replace-objects] [--bare]', '           [--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]', '           <command> [<args>]', ''], 'exit_status': 129, 'stdout': ['']}
*** time: 0.11431 ***