vim-polyglot/indent/dart.vim

let files = filter(globpath(&rtp, 'indent/dart.vim', 1, 1), { _, v -> v !~ "vim-polyglot" && v !~ $VIMRUNTIME && v !~ "after" })
if len(files) > 0
  exec 'source ' . files[0]
  finish
endif
if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'dart') == -1

if exists('b:did_indent')
  finish
endif
let b:did_indent = 1

setlocal cindent
setlocal cinoptions+=j1,J1,(2s,u2s,U1,m1,+2s

setlocal indentexpr=DartIndent()

let b:undo_indent = 'setl cin< cino<'

if exists('*DartIndent')
  finish
endif

function! DartIndent()
  " Default to cindent in most cases
  let indentTo = cindent(v:lnum)

  let previousLine = getline(prevnonblank(v:lnum - 1))
  let currentLine = getline(v:lnum)

  " Don't indent after an annotation
  if previousLine =~# '^\s*@.*$'
    let indentTo = indent(v:lnum - 1)
  endif

  " Indent after opening List literal
  if previousLine =~# '\[$' && !(currentLine =~# '^\s*\]')
    let indentTo = indent(v:lnum - 1) + &shiftwidth
  endif

  return indentTo
endfunction

endif