Update

autoload/dart.vim

@@ -0,0 +1,70 @@
+if !exists('g:polyglot_disabled') || index(g:polyglot_disabled, 'dart') == -1
+  
+
+function! s:error(text) abort
+  echohl Error
+  echomsg printf('[dart-vim-plugin] %s', a:text)
+  echohl None
+endfunction
+
+function! s:cexpr(errorformat, joined_lines) abort
+  let temp_errorfomat = &errorformat
+  try
+    let &errorformat = a:errorformat
+    cexpr a:joined_lines
+    copen
+  finally
+    let &errorformat = temp_errorfomat
+  endtry
+endfunction
+
+function! dart#fmt(q_args) abort
+  if executable('dartfmt')
+    let path = expand('%:p:gs:\:/:')
+    if filereadable(path)
+      let joined_lines = system(printf('dartfmt %s %s', a:q_args, shellescape(path)))
+      if 0 == v:shell_error
+        silent % delete _
+        silent put=joined_lines
+        silent 1 delete _
+      else
+        call s:cexpr('line %l\, column %c of %f: %m', joined_lines)
+      endif
+    else
+      call s:error(printf('cannot read a file: "%s"', path))
+    endif
+  else
+    call s:error('cannot execute binary file: dartfmt')
+  endif
+endfunction
+
+function! dart#analyzer(q_args) abort
+  if executable('dartanalyzer')
+    let path = expand('%:p:gs:\:/:')
+    if filereadable(path)
+      let joined_lines = system(printf('dartanalyzer %s %s', a:q_args, shellescape(path)))
+      call s:cexpr('%m (%f\, line %l\, col %c)', joined_lines)
+    else
+      call s:error(printf('cannot read a file: "%s"', path))
+    endif
+  else
+    call s:error('cannot execute binary file: dartanalyzer')
+  endif
+endfunction
+
+function! dart#tojs(q_args) abort
+  if executable('dart2js')
+    let path = expand('%:p:gs:\:/:')
+    if filereadable(path)
+      let joined_lines = system(printf('dart2js %s %s', a:q_args, shellescape(path)))
+      call s:cexpr('%m (%f\, line %l\, col %c)', joined_lines)
+    else
+      call s:error(printf('cannot read a file: "%s"', path))
+    endif
+  else
+    call s:error('cannot execute binary file: dartanalyzer')
+  endif
+endfunction
+
+
+endif