Add private field modifier to classes

pangloss#1237

Author: mantoni

syntax/javascript.vim

@@ -145,7 +145,7 @@ syntax region  jsParenFor           contained matchgroup=jsParensFor           s
 syntax region  jsParenSwitch        contained matchgroup=jsParensSwitch        start=/(/  end=/)/  contains=@jsExpression skipwhite skipempty nextgroup=jsSwitchBlock extend fold
 syntax region  jsParenCatch         contained matchgroup=jsParensCatch         start=/(/  end=/)/  skipwhite skipempty nextgroup=jsTryCatchBlock extend fold
 syntax region  jsFuncArgs           contained matchgroup=jsFuncParens          start=/(/  end=/)/  contains=jsFuncArgCommas,jsComment,jsFuncArgExpression,jsDestructuringBlock,jsDestructuringArray,jsRestExpression,jsFlowArgumentDef skipwhite skipempty nextgroup=jsCommentFunction,jsFuncBlock,jsFlowReturn extend fold
-syntax region  jsClassBlock         contained matchgroup=jsClassBraces         start=/{/  end=/}/  contains=jsClassFuncName,jsClassMethodType,jsArrowFunction,jsArrowFuncArgs,jsComment,jsGenerator,jsDecorator,jsClassProperty,jsClassPropertyComputed,jsClassStringKey,jsAsyncKeyword,jsNoise extend fold
+syntax region  jsClassBlock         contained matchgroup=jsClassBraces         start=/{/  end=/}/  contains=jsClassFuncName,jsClassMethodType,jsArrowFunction,jsArrowFuncArgs,jsComment,jsGenerator,jsDecorator,jsClassProperty,jsClassPropertyComputed,jsClassStringKey,jsAsyncKeyword,jsModifier,jsNoise extend fold
 syntax region  jsFuncBlock          contained matchgroup=jsFuncBraces          start=/{/  end=/}/  contains=@jsAll extend fold
 syntax region  jsIfElseBlock        contained matchgroup=jsIfElseBraces        start=/{/  end=/}/  contains=@jsAll extend fold
 syntax region  jsTryCatchBlock      contained matchgroup=jsTryCatchBraces      start=/{/  end=/}/  contains=@jsAll skipwhite skipempty nextgroup=jsCatch,jsFinally extend fold
@@ -184,6 +184,7 @@ exe 'syntax match jsArrowFunction /_\ze\s*=>/    skipwhite skipempty nextgroup=j
 " Classes
 syntax keyword jsClassKeyword           contained class
 syntax keyword jsExtendsKeyword         contained extends skipwhite skipempty nextgroup=@jsExpression
+syntax match   jsModifier               contained /\#/
 syntax match   jsClassNoise             contained /\./
 syntax match   jsClassFuncName          contained /\<\K\k*\ze\s*[(<]/ skipwhite skipempty nextgroup=jsFuncArgs,jsFlowClassFunctionGroup
 syntax match   jsClassMethodType        contained /\<\%([gs]et\|static\|accessor\)\ze\s\+\K\k*/ skipwhite skipempty nextgroup=jsAsyncKeyword,jsClassFuncName,jsClassProperty
@@ -237,7 +238,7 @@ if exists("javascript_plugin_flow")
 endif
 
 syntax cluster jsExpression  contains=jsBracket,jsParen,jsObject,jsTernaryIf,jsTaggedTemplate,jsTemplateString,jsString,jsRegexpString,jsNumber,jsFloat,jsOperator,jsOperatorKeyword,jsBooleanTrue,jsBooleanFalse,jsNull,jsFunction,jsArrowFunction,jsGlobalObjects,jsExceptions,jsFutureKeys,jsDomErrNo,jsDomNodeConsts,jsHtmlEvents,jsFuncCall,jsUndefined,jsNan,jsPrototype,jsBuiltins,jsNoise,jsClassDefinition,jsArrowFunction,jsArrowFuncArgs,jsParensError,jsComment,jsArguments,jsThis,jsSuper,jsDo,jsForAwait,jsAsyncKeyword,jsStatement,jsDot
-syntax cluster jsAll         contains=@jsExpression,jsStorageClass,jsConditional,jsWhile,jsFor,jsReturn,jsException,jsTry,jsNoise,jsBlockLabel,jsBlock
+syntax cluster jsAll         contains=@jsExpression,jsStorageClass,jsConditional,jsWhile,jsFor,jsReturn,jsException,jsTry,jsNoise,jsBlockLabel,jsBlock,jsModifier
 
 " Define the default highlighting.
 " For version 5.7 and earlier: only when not done already
@@ -305,6 +306,7 @@ if version >= 508 || !exists("did_javascript_syn_inits")
   HiLink jsOperator             Operator
   HiLink jsOf                   Operator
   HiLink jsStorageClass         StorageClass
+  HiLink jsModifier             StorageClass
   HiLink jsClassKeyword         Keyword
   HiLink jsExtendsKeyword       Keyword
   HiLink jsThis                 Special