Try to expand type declaration highlighting

vim/after/syntax/javascript.vim

@@ -3,23 +3,31 @@ syn clear   jsFutureKeys
 syn keyword jsFutureKeys      final implements goto long synchronized volatile transient float boolean protected abstract native double short char enum throws byte int package
 
 syn keyword tsAccessibility   public private
-syn keyword tsPrimitives      string any number object
+syn keyword tsPrimitives      string any number object void
 syn keyword tsInterface       interface nextgroup=tsInterfaceType,jsExtend skipwhite
-syn keyword jsExtend          extends nextgroup=tsInterfaceType skipwhite
+syn keyword jsExtend          extends nextgroup=tsInterfaceType,tsType skipwhite
 syn match   tsInterfaceType   /\w\+/ nextgroup=jsBlock skipwhite contained
 
+syn cluster tsKeyword         contains=@jsFutureKeys,tsAccessibility,tsPrimitives,tsInterface,jsExtend
+
 syn keyword jsExport          export nextgroup=@jsAll,jsModuleGroup,jsExportDefault,jsModuleAsterisk,jsModuleKeyword,jsFlowTypeStatement,tsInterface  skipwhite skipempty
 syn region  jsClassBlock      matchgroup=jsClassBraces start=/{/ end=/}/  contained extend fold contains=jsClassFuncName,jsClassMethodType,jsArrowFunction,jsArrowFuncArgs,jsComment,jsGenerator,jsDecorator,jsClassProperty,jsClassPropertyComputed,jsClassStringKey,jsAsyncKeyword,jsNoise,tsAccessibility
-syn region  jsFuncArgs        matchgroup=jsFuncParens start=/(/ end=/)/  contains=jsFuncArgCommas,jsComment,jsFuncArgExpression,jsDestructuringBlock,jsDestructuringArray,jsRestExpression,jsFlowArgumentDef,tsVariableType nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn,tsFuncReturnType skipwhite skipempty contained extend fold
+syn match   jsArrowFuncArgs   /\<\K\k*\ze\s*=>/  extend contains=jsFuncArgs,tsPrimitives nextgroup=jsArrowFunction skipwhite skipempty
+syn region  jsParen           matchgroup=jsParens start=/(/ end=/)/  extend fold contains=@jsExpression,tsVariableType,tsPrimitives nextgroup=jsFlowDefinition,tsVariableType
+syn region  jsFuncArgs        matchgroup=jsFuncParens start=/(/ end=/)/  contains=jsFuncArgCommas,jsComment,jsFuncArgExpression,jsDestructuringBlock,jsDestructuringArray,jsRestExpression,jsFlowArgumentDef,tsVariableType,tsPrimitives,jsOperator  nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn,tsFuncReturnType skipwhite skipempty contained extend fold
 "syn region jsCommentFunction start=+//+ end=/$/  contained keepend extend contains=jsCommentTodo,@Spell nextgroup=jsFuncBlock,jsFlowReturn skipwhite skipempty start=+/\*+ end=+\*/+  contained keepend extend fold contains=jsCommentTodo,@Spell nextgroup=jsFuncBlock,jsFlowReturn skipwhite skipempty
 "syn match  jsClassFuncName   /\<\K\k*\ze\s*[(<]/  nextgroup=jsFuncArgs,jsFlowClassFunctionGroup skipwhite contained skipempty
 syn match   jsVariableDef     /\<\K\k*/  nextgroup=jsFlowDefinition,tsVariableType skipwhite skipempty contained
 syn match   jsBlockLabel      /\<\K\k*?\?\s*::\@!/  contains=jsNoise nextgroup=jsBlock skipwhite skipempty
 
-syn match   tsVariableType    /:\s\+\w\+\(.\w\+\)*/ nextgroup=jsFlowDefinition contains=tsTypeDecl,tsType skipwhite contained
-syn match   tsFuncReturnType  /:\s\+\w\+\(.\w\+\)*/ nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn,jsFuncBraces contains=tsTypeDecl,tsType skipwhite contained
+"syn region jsClassDefinition  start=/\<class\>/ end=/\(\<extends\>\s\+\)\@<!{\@=/  contains=jsClassKeyword,jsExtendsKeyword,jsClassNoise,@jsExpression,jsFlowClassGroup,tsType,tsTypeArgAngleBrackets nextgroup=jsCommentClass,jsClassBlock,jsFlowClassGroup skipwhite skipempty
+syn region jsClassDefinition  start=/\<class\>/ end=/\(\<extends\>\s\+\)\@<!{\@=/  contains=jsClassKeyword,jsExtendsKeyword,jsClassNoise,@jsExpression,jsFlowClassGroup,tsPrimitives nextgroup=jsCommentClass,jsClassBlock,jsFlowClassGroup skipwhite skipempty
+
+syn match   tsVariableType    /:\s\+\w\+\(.\w\+\)*/ nextgroup=jsFlowDefinition contains=tsTypeDecl,tsType,tsPrimitives,tsTypeArg skipwhite contained
+syn match   tsFuncReturnType  /:\s\+\w\+\(.\w\+\)*/ nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn,jsFuncBraces,tsTypeArg contains=tsTypeDecl,tsType,tsTypeArg skipwhite contained
 syn match   tsTypeDecl        /:/ contained nextgroup=tsType
-syn match   tsType            /\w\+(\.\w\+)*/ contained
+syn match   tsType            /\w\+(\.\w\+)*/ nextgroup=tsTypeArg contained
+syn region  tsTypeArg         start=/</ end=/>/ matchgroup=tsTypeArgAngleBrackets contains=tsType,tsTypeArg,tsPrimitives,tsKeyword nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn,jsFuncBraces skipwhite contained
 
 " Override the default definitions, adding/removing as necessary
 syn cluster jsAll           contains=@jsExpression,jsStorageClass,jsConditional,jsRepeat,jsReturn,jsException,jsTry,jsNoise,jsBlockLabel,tsPrimitives
@@ -35,3 +43,4 @@ hi link tsPrimitives Special
 hi link tsType Type
 hi link tsFuncReturnType tsType
 hi link tsVariableType tsType
+hi link tsKeyword special