Async.Promise: Prefer v:t_*

Author: rhysd

autoload/vital/__vital__/Async/Promise.vim

@@ -8,9 +8,6 @@ let s:PENDING = 0
 let s:FULFILLED = 1
 let s:REJECTED = 2
 
-let s:DICT_T = type({})
-let s:NULL_T = type(v:null)
-
 " @vimlint(EVL103, 1, a:resolve)
 " @vimlint(EVL103, 1, a:reject)
 function! s:noop(resolve, reject) abort
@@ -37,7 +34,7 @@ endfunction
 
 " ... is added to use this function as a callback of timer_start()
 function! s:_invoke_callback(settled, promise, callback, result, ...) abort
-  let has_callback = type(a:callback) != s:NULL_T
+  let has_callback = type(a:callback) != v:t_none
   let success = 1
   let Err = v:null
   if has_callback
@@ -79,7 +76,7 @@ function! s:_publish(promise, ...) abort
       throw 'vital: Async.Promise: Cannot publish a pending promise'
     endif
     let child = a:promise._children[i]
-    if type(child) != s:NULL_T
+    if type(child) != v:t_none
       call s:_invoke_callback(settled, child, l:CB, a:promise._result)
     else
       call l:CB(a:promise._result)
@@ -223,7 +220,7 @@ function! s:is_available() abort
 endfunction
 
 function! s:is_promise(maybe_promise) abort
-  return type(a:maybe_promise) == s:DICT_T && has_key(a:maybe_promise, '_vital_promise')
+  return type(a:maybe_promise) == v:t_dict && has_key(a:maybe_promise, '_vital_promise')
 endfunction
 
 function! s:_promise_then(...) dict abort