fix: secret function

lib/secret.js

@@ -31,21 +31,9 @@ class Secret {
 }
 
 function secretObject(obj, fieldsToHide = []) {
-  const handler = {
-    get(obj, prop) {
-      if (prop === 'toString') {
-        return function () {
-          const maskedObject = deepClone(obj);
-          fieldsToHide.forEach(f => maskedObject[f] = '****');
-          return JSON.stringify(maskedObject);
-        };
-      }
-
-      return obj[prop];
-    },
-  };
-
-  return new Proxy(obj, handler);
+  const maskedObject = deepClone(obj);
+  fieldsToHide.forEach(f => maskedObject[f] = new Secret(maskedObject[f]));
+  return maskedObject;
 }
 
 module.exports = Secret;

test/unit/secret_test.js

@@ -0,0 +1,19 @@
+const expect = require('expect');
+const Secret = require('../../lib/secret');
+
+describe('Secret tests', () => {
+  it('should be the Secret instance', () => {
+    const string = Secret.secret('hello');
+    expect(string).toBeInstanceOf(Secret);
+  });
+
+  it('should be the Secret instance when using as object', () => {
+    const obj = Secret.secret({ password: 'world' }, 'password');
+    expect(obj.password).toBeInstanceOf(Secret);
+  });
+
+  it('should mask the field when provided', () => {
+    const obj = Secret.secret({ password: 'world' }, 'password');
+    expect(obj.password.getMasked()).toBe('*****');
+  });
+});