From a92317c5562c281fb6a5bbe6f872854b6b242094 Mon Sep 17 00:00:00 2001
From: Karl Fleischmann <fleischmann.karl@gmail.com>
Date: Sun, 10 Jun 2018 13:54:14 +0200
Subject: [PATCH 1/3] Add syntax highlighting for flow comment types

- Match comment type include and annotation region.
- Allow FlowType syntax inside of these regions.
- Highlight single colon to represent special meaning (kept verbosely in
  type annotation).
---
 after/syntax/javascript.vim | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
 create mode 100644 after/syntax/javascript.vim

diff --git a/after/syntax/javascript.vim b/after/syntax/javascript.vim
new file mode 100644
index 0000000..7d4411e
--- /dev/null
+++ b/after/syntax/javascript.vim
@@ -0,0 +1,33 @@
+if exists("b:current_syntax")
+  let s:current_syntax=b:current_syntax
+  unlet b:current_syntax
+endif
+
+" classify flow flag
+syntax match flowAnnotationFlag "@flow" contained
+  \ containedin=jsComment
+
+" classify keywords, that indicate flow comment include
+syntax match flowTypeCommentKeyword "::"
+syntax match flowTypeCommentKeyword "flow-include"
+
+" classify flow comment include and type annotation regions
+" - \/\*                    - (= "/*") begin of a js block comment
+" - \%(::\?\|flow-include\) - check for keywords to begin type comments
+" - \@=                     - check but don't include in the matched
+"                             group
+" - \*\/                    - (= "*/") end of a js block comment
+syntax region flowTypeComment matchgroup=jsComment
+  \ transparent fold keepend
+  \ start="\/\*\%(::\?\|flow-include\)\@=" end="\*\/"
+  \ contains=jsFlowArgumentDef,jsFlowClassGroup,jsFlowType,
+  \          jsFlowTypeStatement,flowTypeCommentKeyword
+  \ containedin=js.*Block,jsClassDefinition,jsFuncArgs
+
+" highlight the appropriate syntax elements accordingly
+highlight default link flowAnnotationFlag Special
+highlight default link flowTypeCommentKeyword Comment
+
+if exists("s:current_syntax")
+  let b:current_syntax=s:current_syntax
+endif

From 971f68dd3a71b2f4ae257822a448a325dd7684a0 Mon Sep 17 00:00:00 2001
From: Karl Fleischmann <fleischmann.karl@gmail.com>
Date: Wed, 13 Jun 2018 22:06:57 +0200
Subject: [PATCH 2/3] Enable function return flow annotations

This commit adds support for flow annotations to statements as the
following:
```
function test() /*: $await<number> */ {}
```
---
 after/syntax/javascript.vim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/after/syntax/javascript.vim b/after/syntax/javascript.vim
index 7d4411e..2cd0bc3 100644
--- a/after/syntax/javascript.vim
+++ b/after/syntax/javascript.vim
@@ -22,7 +22,7 @@ syntax region flowTypeComment matchgroup=jsComment
   \ start="\/\*\%(::\?\|flow-include\)\@=" end="\*\/"
   \ contains=jsFlowArgumentDef,jsFlowClassGroup,jsFlowType,
   \          jsFlowTypeStatement,flowTypeCommentKeyword
-  \ containedin=js.*Block,jsClassDefinition,jsFuncArgs
+  \ containedin=js.*Block,jsClassDefinition,jsCommentFunction,jsFuncArgs
 
 " highlight the appropriate syntax elements accordingly
 highlight default link flowAnnotationFlag Special

From 3244412d483f60cb8976d92c0800aa63b61855ae Mon Sep 17 00:00:00 2001
From: Karl Fleischmann <fleischmann.karl@gmail.com>
Date: Thu, 14 Jun 2018 09:32:37 +0200
Subject: [PATCH 3/3] Bypass comment leader on type annotations

Adding `f:/*::` skips comment continuations on new lines, when in a
type annotation comment. This needs to be prepended onto the existing
comments, to remain the behavior of javascript's block comments.
---
 after/ftplugin/javascript.vim | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/after/ftplugin/javascript.vim b/after/ftplugin/javascript.vim
index ecc25bc..b142b3a 100644
--- a/after/ftplugin/javascript.vim
+++ b/after/ftplugin/javascript.vim
@@ -13,3 +13,8 @@ endif
 if exists('&omnifunc') && g:flow#omnifunc
   setl omnifunc=flowcomplete#Complete
 endif
+
+" Setup `/*::` to not be continued as a javascript block comment
+" - Prepend the currently setup `comments` options, so that '/*' is
+"   still evaluated as before
+let &comments = "f:/*::," . &comments