feat(core): Enhanced JWT handling and key management

ts/smartjwt.classes.smartjwt.ts

@@ -1,5 +1,8 @@
 import * as plugins from './smartjwt.plugins.js';
 
+// Define the IWithJwt interface with a constraint that T must be an object
+export type IObjectWithJwt<T extends object> = T & { jwt: string };
+
 /**
  * A class to create and validate JWTs and their keys
  */
@@ -81,4 +84,33 @@ export class SmartJwt<T extends object = any> {
   public async init() {
     await this.createNewKeyPair();
   }
+
+
+
+  public isObjectWithJwt<T extends object>(
+    object: unknown,
+  ): object is IObjectWithJwt<T> {
+    return (
+      typeof object === 'object' &&
+      object !== null &&
+      'jwt' in object &&
+      typeof (object as IObjectWithJwt<T>).jwt === 'string'
+    );
+  }
+
+  public jwtObjectGuard = new plugins.smartguard.Guard(async (dataArg: IObjectWithJwt<any>) => {
+    const jwtData = this.verifyJWTAndGetData(dataArg.jwt);
+    // check all other properties wether they match with jwtData
+    for (const key in dataArg) {
+      if (key !== 'jwt') {
+        if (jwtData[key] !== dataArg[key]) {
+          return false;
+        }
+      }
+    }
+    return true;
+  }, {
+    name: 'jwtObjectGuard',
+    failedHint: 'is not a valid jwt object',
+  })
 }