[javascript mode] Handle parenthesized typescript types

Closes codemirror#5332

Author: marijnh

mode/javascript/javascript.js

@@ -572,6 +572,7 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
     if (type == "[") return cont(pushlex("]"), commasep(typeexpr, "]", ","), poplex, afterType)
     if (type == "{") return cont(pushlex("}"), commasep(typeprop, "}", ",;"), poplex, afterType)
     if (type == "(") return cont(commasep(typearg, ")"), maybeReturnType)
+    if (type == "<") return cont(commasep(typeexpr, ">"), typeexpr)
   }
   function maybeReturnType(type) {
     if (type == "=>") return cont(typeexpr)
@@ -588,9 +589,10 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
       return cont(expression, maybetype, expect("]"), typeprop)
     }
   }
-  function typearg(type) {
-    if (type == "variable") return cont(typearg)
-    else if (type == ":") return cont(typeexpr)
+  function typearg(type, value) {
+    if (type == "variable" && cx.stream.match(/^\s*[?:]/, false) || value == "?") return cont(typearg)
+    if (type == ":") return cont(typeexpr)
+    return pass(typeexpr)
   }
   function afterType(type, value) {
     if (value == "<") return cont(pushlex(">"), commasep(typeexpr, ">"), poplex, afterType)

mode/javascript/test.js

@@ -402,6 +402,12 @@
      "  [def META],",
      "}")
 
+  TS("parenthesized type",
+     "[keyword class] [def Foo] {",
+     "  [property x] [operator =] [keyword new] [variable A][operator <][type B], [type string][operator |](() [operator =>] [type void])[operator >]();",
+     "  [keyword private] [property bar]();",
+     "}")
+
   var jsonld_mode = CodeMirror.getMode(
     {indentUnit: 2},
     {name: "javascript", jsonld: true}