diff --git a/runtime/JavaScript/src/antlr4/Lexer.d.ts b/runtime/JavaScript/src/antlr4/Lexer.d.ts
index fe32aa7b4f..e8de0e1f65 100644
--- a/runtime/JavaScript/src/antlr4/Lexer.d.ts
+++ b/runtime/JavaScript/src/antlr4/Lexer.d.ts
@@ -22,7 +22,9 @@ export declare class Lexer extends Recognizer<number> {
     nextToken(): Token;
     skip(): void;
     more(): void;
-    more(m: number): void;
+    getModeStack(): number[];
+    getMode(): number;
+    setMode(m: number): void;    
     pushMode(m: number): void;
     popMode(): number;
     emitToken(token: Token): void;
diff --git a/runtime/JavaScript/src/antlr4/Lexer.js b/runtime/JavaScript/src/antlr4/Lexer.js
index 8ff0a89a53..c6a65647fd 100644
--- a/runtime/JavaScript/src/antlr4/Lexer.js
+++ b/runtime/JavaScript/src/antlr4/Lexer.js
@@ -121,7 +121,7 @@ export default class Lexer extends Recognizer {
 							this.notifyListeners(e); // report error
 							this.recover(e);
 						} else {
-                            console.log(e.stack);
+							console.log(e.stack);
 							throw e;
 						}
 					}
@@ -173,6 +173,18 @@ export default class Lexer extends Recognizer {
 		this._mode = m;
 	}
 
+	getMode() {
+		return this._mode;
+	}
+
+	setMode(m) {
+		this._mode = m;
+	}
+
+	getModeStack() {
+		return this._modeStack;
+	}
+
 	pushMode(m) {
 		if (this._interp.debug) {
 			console.log("pushMode " + m);
diff --git a/runtime/JavaScript/src/antlr4/Recognizer.d.ts b/runtime/JavaScript/src/antlr4/Recognizer.d.ts
index d77927c9a2..a01343c121 100644
--- a/runtime/JavaScript/src/antlr4/Recognizer.d.ts
+++ b/runtime/JavaScript/src/antlr4/Recognizer.d.ts
@@ -6,4 +6,7 @@ export declare class Recognizer<TSymbol> {
 
     removeErrorListeners(): void;
     addErrorListener(listener: ErrorListener<TSymbol>): void;
+    getErrorListenerDispatch(): ErrorListener<TSymbol>;
+    getLiteralNames(): string[] | [];
+    getSymbolicNames(): string[] | [];
 }
diff --git a/runtime/JavaScript/src/antlr4/Token.d.ts b/runtime/JavaScript/src/antlr4/Token.d.ts
index 87fb12d1f5..7a8e5b70a5 100644
--- a/runtime/JavaScript/src/antlr4/Token.d.ts
+++ b/runtime/JavaScript/src/antlr4/Token.d.ts
@@ -1,9 +1,10 @@
-import {CharStream} from "./CharStream";
+import { TokenSource } from "./TokenSource";
+import { CharStream } from "./CharStream";
 
 export declare class Token {
 
+    static INVALID_TYPE: number;
     static EOF: number;
-    
     static DEFAULT_CHANNEL: number;
     static HIDDEN_CHANNEL: number;
 
@@ -18,5 +19,6 @@ export declare class Token {
 
     clone(): Token;
     cloneWithType(type: number): Token;
+    getTokenSource(): TokenSource;
     getInputStream(): CharStream;
 }