[javascript mode] Improve TypeScript support

Add type conditionals, fix parenthesized types, support quoted property
names, fix handling of type parameters in type definitions, and handle
call signatures in interfaces and object types.

Closes #5737

Author: marijnh

mode/javascript/javascript.js

@@ -376,7 +376,7 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
       } else if (isTS && (value == "module" || value == "enum" || value == "type") && cx.stream.match(/^\s*\w/, false)) {
         cx.marked = "keyword"
         if (value == "enum") return cont(enumdef);
-        else if (value == "type") return cont(typeexpr, expect("operator"), typeexpr, expect(";"));
+        else if (value == "type") return cont(typename, expect("operator"), typeexpr, expect(";"));
         else return cont(pushlex("form"), pattern, expect("{"), pushlex("}"), block, poplex, poplex)
       } else if (isTS && value == "namespace") {
         cx.marked = "keyword"
@@ -574,7 +574,7 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
   }
   function maybetype(type, value) {
     if (isTS) {
-      if (type == ":") return cont(typeexpr);
+      if (type == ":" || value == "in") return cont(typeexpr);
       if (value == "?") return cont(maybetype);
     }
   }
@@ -591,9 +591,9 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
     }
   }
   function typeexpr(type, value) {
-    if (value == "keyof" || value == "typeof") {
+    if (value == "keyof" || value == "typeof" || value == "infer") {
       cx.marked = "keyword"
-      return cont(value == "keyof" ? typeexpr : expressionNoComma)
+      return cont(value == "typeof" ? expressionNoComma : typeexpr)
     }
     if (type == "variable" || value == "void") {
       cx.marked = "type"
@@ -602,7 +602,7 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
     if (type == "string" || type == "number" || type == "atom") return cont(afterType);
     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(typearg, ")"), maybeReturnType, afterType)
     if (type == "<") return cont(commasep(typeexpr, ">"), typeexpr)
   }
   function maybeReturnType(type) {
@@ -612,26 +612,28 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
     if (type == "variable" || cx.style == "keyword") {
       cx.marked = "property"
       return cont(typeprop)
-    } else if (value == "?") {
+    } else if (value == "?" || type == "number" || type == "string") {
       return cont(typeprop)
     } else if (type == ":") {
       return cont(typeexpr)
     } else if (type == "[") {
-      return cont(expression, maybetype, expect("]"), typeprop)
+      return cont(expect("variable"), maybetype, expect("]"), typeprop)
     } else if (type == "(") {
-      return cont(pushlex(")"), commasep(funarg, ")"), poplex, typeprop)
+      return pass(functiondecl, typeprop)
     }
   }
   function typearg(type, value) {
     if (type == "variable" && cx.stream.match(/^\s*[?:]/, false) || value == "?") return cont(typearg)
     if (type == ":") return cont(typeexpr)
+    if (type == "spread") return cont(typearg)
     return pass(typeexpr)
   }
   function afterType(type, value) {
     if (value == "<") return cont(pushlex(">"), commasep(typeexpr, ">"), poplex, afterType)
     if (value == "|" || type == "." || value == "&") return cont(typeexpr)
-    if (type == "[") return cont(expect("]"), afterType)
+    if (type == "[") return cont(typeexpr, expect("]"), afterType)
     if (value == "extends" || value == "implements") { cx.marked = "keyword"; return cont(typeexpr) }
+    if (value == "?") return cont(typeexpr, expect(":"), typeexpr)
   }
   function maybeTypeArgs(_, value) {
     if (value == "<") return cont(pushlex(">"), commasep(typeexpr, ">"), poplex, afterType)
@@ -710,6 +712,14 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
     if (type == "(") return cont(pushcontext, pushlex(")"), commasep(funarg, ")"), poplex, mayberettype, popcontext);
     if (isTS && value == "<") return cont(pushlex(">"), commasep(typeparam, ">"), poplex, functiondecl)
   }
+  function typename(type, value) {
+    if (type == "keyword" || type == "variable") {
+      cx.marked = "type"
+      return cont(typename)
+    } else if (value == "<") {
+      return cont(pushlex(">"), commasep(typeparam, ">"), poplex)
+    }
+  }
   function funarg(type, value) {
     if (value == "@") cont(expression, funarg)
     if (type == "spread") return cont(funarg);
@@ -744,12 +754,14 @@ CodeMirror.defineMode("javascript", function(config, parserConfig) {
       cx.marked = "property";
       return cont(isTS ? classfield : functiondef, classBody);
     }
+    if (type == "number" || type == "string") return cont(isTS ? classfield : functiondef, classBody);
     if (type == "[")
       return cont(expression, maybetype, expect("]"), isTS ? classfield : functiondef, classBody)
     if (value == "*") {
       cx.marked = "keyword";
       return cont(classBody);
     }
+    if (isTS && type == "(") return pass(functiondecl, classBody)
     if (type == ";") return cont(classBody);
     if (type == "}") return cont();
     if (value == "@") return cont(expression, classBody)