added in custom error classes

added in the custom error classes that are used for the verify tokens.

jsonwebtoken/jsonwebtoken.d.ts

@@ -7,6 +7,24 @@
 
 declare module "jsonwebtoken" {
 
+    export class JsonWebTokenError extends Error {
+        inner: Error;
+
+        constructor(message: string, error?: Error);
+    }
+
+    export class TokenExpiredError extends JsonWebTokenError {
+        expiredAt: number;
+
+        constructor(message: string, expiredAt: number);
+    }
+
+    export class NotBeforeError extends JsonWebTokenError {
+        date: Date;
+
+        constructor(message: string, date: Date);
+    }
+
     export interface SignOptions {
         /**
          * Signature algorithm. Could be one of these values :
@@ -53,7 +71,7 @@ declare module "jsonwebtoken" {
     }
 
     export interface VerifyCallback {
-        (err: Error, decoded: any): void;
+        (err: JsonWebTokenError | TokenExpiredError | NotBeforeError, decoded: any): void;
     }
 
     export interface SignCallback {