feat: Add comprehensive query filters guide and enhance type safety for MongoDB queries

- Introduced a detailed guide on query filters in the README, covering basic filtering, comparison operators, array operators, logical operators, element operators, and advanced filtering patterns.
- Implemented a type-safe filtering system in `classes.doc.ts` with `MongoFilterCondition` and `MongoFilter` types to support MongoDB operators while maintaining nested type safety.
- Enhanced error handling for invalid operators and conditions in the filtering logic.
- Added extensive tests for various filtering scenarios, including basic, comparison, array, logical, and complex filters, ensuring robust functionality and performance.
- Implemented security measures to prevent the use of dangerous operators like `$where` and validate operator usage.

package.json

@@ -7,7 +7,7 @@
   "typings": "dist_ts/index.d.ts",
   "type": "module",
   "scripts": {
-    "test": "tstest test/ --verbose",
+    "test": "tstest test/ --verbose.  --logfile --timeout 120",
     "testSearch": "tsx test/test.search.ts",
     "build": "tsbuild --web --allowimplicitany",
     "buildDocs": "tsdoc"
@@ -37,10 +37,10 @@
     "mongodb": "^6.18.0"
   },
   "devDependencies": {
-    "@git.zone/tsbuild": "^2.6.4",
+    "@git.zone/tsbuild": "^2.6.7",
     "@git.zone/tsrun": "^1.2.44",
-    "@git.zone/tstest": "^2.3.2",
+    "@git.zone/tstest": "^2.3.5",
-    "@push.rocks/qenv": "^6.0.5",
+    "@push.rocks/qenv": "^6.1.3",
     "@push.rocks/tapbundle": "^6.0.3",
     "@types/node": "^22.15.2"
   },

readme.md

@@ -132,6 +132,338 @@ await foundUser.save();
 await foundUser.delete();
 ```
 
+## 🔍 Query Filters Guide
+
+SmartData provides a comprehensive and type-safe filtering system that supports all MongoDB query operators while preventing dangerous operations like `$where` for security.
+
+### Basic Filtering
+
+```typescript
+// Simple equality - find users with exact name
+const johns = await User.getInstances({ name: 'John Doe' });
+
+// Multiple conditions (implicit AND)
+const activeAdults = await User.getInstances({ 
+  status: 'active',
+  age: { $gte: 18 }
+});
+
+// Nested object fields - use dot notation
+const recentUsers = await User.getInstances({
+  'metadata.lastLogin': { $gte: new Date('2024-01-01') },
+  'metadata.loginCount': { $gt: 5 }
+});
+```
+
+### Comparison Operators
+
+All standard MongoDB comparison operators are supported:
+
+```typescript
+// Greater than / Greater than or equal
+const adults = await User.getInstances({ age: { $gte: 18 } });
+const seniors = await User.getInstances({ age: { $gt: 65 } });
+
+// Less than / Less than or equal
+const youth = await User.getInstances({ age: { $lt: 25 } });
+const under30 = await User.getInstances({ age: { $lte: 30 } });
+
+// Not equal
+const notPending = await User.getInstances({ status: { $ne: 'pending' } });
+
+// Combine multiple comparisons
+const middleAged = await User.getInstances({
+  age: { $gte: 30, $lt: 50 }
+});
+```
+
+### Array Operators
+
+SmartData fully supports MongoDB's array query operators:
+
+```typescript
+// $in - Match any value in array
+const adminsAndMods = await User.getInstances({ 
+  role: { $in: ['admin', 'moderator'] } 
+});
+
+// $nin - Match none of the values
+const regularUsers = await User.getInstances({ 
+  role: { $nin: ['admin', 'moderator'] } 
+});
+
+// $all - Array contains all specified elements
+const fullStackDevs = await User.getInstances({ 
+  skills: { $all: ['javascript', 'nodejs', 'mongodb'] } 
+});
+
+// $size - Array has specific length
+const usersWithThreeSkills = await User.getInstances({ 
+  skills: { $size: 3 } 
+});
+
+// $elemMatch - Match array elements with multiple conditions
+const ordersWithExpensiveItems = await Order.getInstances({
+  items: { 
+    $elemMatch: { 
+      product: 'laptop',
+      quantity: { $gte: 2 },
+      price: { $gt: 1000 }
+    }
+  }
+});
+```
+
+### Working with Arrays
+
+```typescript
+// Find documents where array field contains a value
+const javascriptUsers = await User.getInstances({
+  tags: { $in: ['javascript'] }  // Users with 'javascript' in tags array
+});
+
+// Find documents where array field contains ALL values
+const expertUsers = await User.getInstances({
+  certifications: { $all: ['mongodb', 'nodejs', 'typescript'] }
+});
+
+// Query nested arrays of objects
+const highValueOrders = await Order.getInstances({
+  'items.price': { $gte: 100 }  // Orders with any item priced >= 100
+});
+
+// Complex array element matching
+const bulkElectronicsOrders = await Order.getInstances({
+  items: {
+    $elemMatch: {
+      category: 'electronics',
+      quantity: { $gte: 5 },
+      discount: { $exists: true }
+    }
+  }
+});
+```
+
+### Logical Operators
+
+Combine multiple conditions with logical operators:
+
+```typescript
+// $or - Match any condition
+const urgentOrHighValue = await Order.getInstances({
+  $or: [
+    { priority: 'urgent' },
+    { totalAmount: { $gte: 1000 } }
+  ]
+});
+
+// $and - Match all conditions (usually implicit, but useful for complex queries)
+const premiumActiveUsers = await User.getInstances({
+  $and: [
+    { subscription: 'premium' },
+    { status: 'active' },
+    { lastLogin: { $gte: new Date(Date.now() - 30*24*60*60*1000) } }
+  ]
+});
+
+// $nor - Match none of the conditions
+const availableProducts = await Product.getInstances({
+  $nor: [
+    { status: 'discontinued' },
+    { inventory: { $lte: 0 } }
+  ]
+});
+
+// $not - Negate a condition
+const nonEmptyArrays = await User.getInstances({
+  tags: { $not: { $size: 0 } }
+});
+
+// Nested logical operations
+const complexQuery = await User.getInstances({
+  $or: [
+    {
+      $and: [
+        { role: 'admin' },
+        { department: 'IT' }
+      ]
+    },
+    {
+      $and: [
+        { role: 'manager' },
+        { yearsExperience: { $gte: 5 } }
+      ]
+    }
+  ]
+});
+```
+
+### Element Operators
+
+Check for field existence and types:
+
+```typescript
+// $exists - Check if field exists
+const usersWithAvatar = await User.getInstances({
+  'profile.avatar': { $exists: true }
+});
+
+const usersWithoutPhone = await User.getInstances({
+  phoneNumber: { $exists: false }
+});
+
+// $type - Check field type (MongoDB BSON types)
+const usersWithStringId = await User.getInstances({
+  id: { $type: 'string' }  // or use type number: 2 for string
+});
+```
+
+### Regular Expressions
+
+Use regex for pattern matching:
+
+```typescript
+// Case-insensitive search
+const johnUsers = await User.getInstances({
+  name: { $regex: '^john', $options: 'i' }
+});
+
+// Email domain matching
+const gmailUsers = await User.getInstances({
+  email: { $regex: '@gmail\.com$' }
+});
+
+// Complex pattern matching
+const validPhones = await User.getInstances({
+  phone: { $regex: '^\+1-\d{3}-\d{3}-\d{4}$' }
+});
+```
+
+### Advanced Filtering Patterns
+
+```typescript
+// Combine multiple operator types
+const targetUsers = await User.getInstances({
+  $and: [
+    { age: { $gte: 25, $lte: 45 } },
+    { status: { $in: ['active', 'premium'] } },
+    { 
+      $or: [
+        { 'subscription.type': 'annual' },
+        { 'subscription.credits': { $gte: 100 } }
+      ]
+    },
+    { tags: { $all: ['verified', 'trusted'] } }
+  ]
+});
+
+// Filter with post-processing validation
+const results = await Product.search('laptop', {
+  filter: { 
+    price: { $lte: 2000 },
+    brand: { $in: ['Apple', 'Dell', 'Lenovo'] }
+  },
+  validate: async (product) => {
+    // Additional custom validation
+    return product.warrantyYears >= 2 && product.inStock;
+  }
+});
+
+// Transaction-safe filtering
+const session = db.startSession();
+await session.withTransaction(async () => {
+  const users = await User.getInstances(
+    { status: 'pending' },
+    { session }  // Pass session for transaction
+  );
+  // Process users within transaction
+});
+```
+
+### Performance Tips
+
+1. **Use Indexes**: Create indexes on frequently filtered fields:
+   ```typescript
+   @index() public status: string;  // Regular index
+   @unI() public email: string;     // Unique index
+   ```
+
+2. **Limit Results**: Use cursors for large datasets:
+   ```typescript
+   const cursor = await User.getCursor({ status: 'active' });
+   await cursor.forEach(async (user) => {
+     // Process one at a time
+   });
+   ```
+
+3. **Projection**: Retrieve only needed fields (using MongoDB native):
+   ```typescript
+   const collection = User.getCollection();
+   const results = await collection.mongoDbCollection
+     .find({ status: 'active' })
+     .project({ name: 1, email: 1 })
+     .toArray();
+   ```
+
+### Security Considerations
+
+SmartData automatically prevents dangerous operations:
+
+```typescript
+// ❌ These will throw errors:
+await User.getInstances({ 
+  $where: 'this.age > 25'  // Blocked: JavaScript execution
+});
+
+await User.getInstances({
+  'user.name': { 'bad.key': 'value' }  // Blocked: dots in keys
+});
+
+// ✅ Safe alternatives:
+await User.getInstances({ 
+  age: { $gt: 25 }  // Use operators instead
+});
+
+await User.getInstances({
+  'user.name': 'value'  // Use dot notation for nested fields
+});
+```
+
+### Common Pitfalls and Solutions
+
+```typescript
+// ❌ Wrong: Array operators need arrays
+await User.getInstances({ 
+  role: { $in: 'admin' }  // Error: $in requires array
+});
+
+// ✅ Correct:
+await User.getInstances({ 
+  role: { $in: ['admin'] }
+});
+
+// ❌ Wrong: Direct array comparison (exact match)
+await User.getInstances({ 
+  tags: 'javascript'  // Only matches if tags = ['javascript'] exactly
+});
+
+// ✅ Correct: Check if array contains element
+await User.getInstances({ 
+  tags: { $in: ['javascript'] }  // Matches if 'javascript' is in tags
+});
+
+// ❌ Wrong: Checking multiple array elements incorrectly
+await User.getInstances({ 
+  skills: 'javascript',
+  skills: 'nodejs'  // Object can't have duplicate keys!
+});
+
+// ✅ Correct: Use $all for multiple elements
+await User.getInstances({ 
+  skills: { $all: ['javascript', 'nodejs'] }
+});
+```
+
 ## 🔥 Advanced Features
 
 ### 🔎 Powerful Search Engine

test/test.filters.ts

@@ -0,0 +1,604 @@
+import { tap, expect } from '@git.zone/tstest/tapbundle';
+import * as smartmongo from '@push.rocks/smartmongo';
+import * as smartunique from '@push.rocks/smartunique';
+import * as smartdata from '../ts/index.js';
+
+const { SmartdataDb, Collection, svDb, unI, index } = smartdata;
+
+let smartmongoInstance: smartmongo.SmartMongo;
+let testDb: smartdata.SmartdataDb;
+
+// Define test document classes
+@Collection(() => testDb)
+class TestUser extends smartdata.SmartDataDbDoc<TestUser, TestUser> {
+  @unI()
+  public id: string = smartunique.shortId();
+
+  @svDb()
+  public name: string;
+
+  @svDb()
+  public age: number;
+
+  @svDb()
+  public email: string;
+
+  @svDb()
+  public roles: string[];
+
+  @svDb()
+  public tags: string[];
+
+  @svDb()
+  public status: 'active' | 'inactive' | 'pending';
+
+  @svDb()
+  public metadata: {
+    lastLogin?: Date;
+    loginCount?: number;
+    preferences?: Record<string, any>;
+  };
+
+  @svDb()
+  public scores: number[];
+
+  constructor(data: Partial<TestUser> = {}) {
+    super();
+    Object.assign(this, data);
+  }
+}
+
+@Collection(() => testDb)
+class TestOrder extends smartdata.SmartDataDbDoc<TestOrder, TestOrder> {
+  @unI()
+  public id: string = smartunique.shortId();
+
+  @svDb()
+  public userId: string;
+
+  @svDb()
+  public items: Array<{
+    product: string;
+    quantity: number;
+    price: number;
+  }>;
+
+  @svDb()
+  public totalAmount: number;
+
+  @svDb()
+  public status: string;
+
+  @svDb()
+  public tags: string[];
+
+  constructor(data: Partial<TestOrder> = {}) {
+    super();
+    Object.assign(this, data);
+  }
+}
+
+// Setup and teardown
+tap.test('should create a test database instance', async () => {
+  smartmongoInstance = await smartmongo.SmartMongo.createAndStart();
+  testDb = new smartdata.SmartdataDb(await smartmongoInstance.getMongoDescriptor());
+  await testDb.init();
+  expect(testDb).toBeInstanceOf(SmartdataDb);
+});
+
+tap.test('should create test data', async () => {
+  // Create test users
+  const users = [
+    new TestUser({
+      name: 'John Doe',
+      age: 30,
+      email: 'john@example.com',
+      roles: ['admin', 'user'],
+      tags: ['javascript', 'nodejs', 'mongodb'],
+      status: 'active',
+      metadata: { loginCount: 5, lastLogin: new Date() },
+      scores: [85, 90, 78]
+    }),
+    new TestUser({
+      name: 'Jane Smith',
+      age: 25,
+      email: 'jane@example.com',
+      roles: ['user'],
+      tags: ['python', 'mongodb'],
+      status: 'active',
+      metadata: { loginCount: 3 },
+      scores: [92, 88, 95]
+    }),
+    new TestUser({
+      name: 'Bob Johnson',
+      age: 35,
+      email: 'bob@example.com',
+      roles: ['moderator', 'user'],
+      tags: ['javascript', 'react', 'nodejs'],
+      status: 'inactive',
+      metadata: { loginCount: 0 },
+      scores: [70, 75, 80]
+    }),
+    new TestUser({
+      name: 'Alice Brown',
+      age: 28,
+      email: 'alice@example.com',
+      roles: ['admin'],
+      tags: ['typescript', 'angular', 'mongodb'],
+      status: 'active',
+      metadata: { loginCount: 10 },
+      scores: [95, 98, 100]
+    }),
+    new TestUser({
+      name: 'Charlie Wilson',
+      age: 22,
+      email: 'charlie@example.com',
+      roles: ['user'],
+      tags: ['golang', 'kubernetes'],
+      status: 'pending',
+      metadata: { loginCount: 1 },
+      scores: [60, 65]
+    })
+  ];
+
+  for (const user of users) {
+    await user.save();
+  }
+
+  // Create test orders
+  const orders = [
+    new TestOrder({
+      userId: users[0].id,
+      items: [
+        { product: 'laptop', quantity: 1, price: 1200 },
+        { product: 'mouse', quantity: 2, price: 25 }
+      ],
+      totalAmount: 1250,
+      status: 'completed',
+      tags: ['electronics', 'priority']
+    }),
+    new TestOrder({
+      userId: users[1].id,
+      items: [
+        { product: 'book', quantity: 3, price: 15 },
+        { product: 'pen', quantity: 5, price: 2 }
+      ],
+      totalAmount: 55,
+      status: 'pending',
+      tags: ['stationery']
+    }),
+    new TestOrder({
+      userId: users[0].id,
+      items: [
+        { product: 'laptop', quantity: 2, price: 1200 },
+        { product: 'keyboard', quantity: 2, price: 80 }
+      ],
+      totalAmount: 2560,
+      status: 'processing',
+      tags: ['electronics', 'bulk']
+    })
+  ];
+
+  for (const order of orders) {
+    await order.save();
+  }
+
+  const savedUsers = await TestUser.getInstances({});
+  const savedOrders = await TestOrder.getInstances({});
+  expect(savedUsers.length).toEqual(5);
+  expect(savedOrders.length).toEqual(3);
+});
+
+// ============= BASIC FILTER TESTS =============
+tap.test('should filter by simple equality', async () => {
+  const users = await TestUser.getInstances({ name: 'John Doe' });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('John Doe');
+});
+
+tap.test('should filter by multiple fields (implicit AND)', async () => {
+  const users = await TestUser.getInstances({ 
+    status: 'active',
+    age: 30
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('John Doe');
+});
+
+tap.test('should filter by nested object fields', async () => {
+  const users = await TestUser.getInstances({
+    'metadata.loginCount': 5
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('John Doe');
+});
+
+// ============= COMPARISON OPERATOR TESTS =============
+tap.test('should filter using $gt operator', async () => {
+  const users = await TestUser.getInstances({
+    age: { $gt: 30 }
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('Bob Johnson');
+});
+
+tap.test('should filter using $gte operator', async () => {
+  const users = await TestUser.getInstances({
+    age: { $gte: 30 }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Bob Johnson', 'John Doe']);
+});
+
+tap.test('should filter using $lt operator', async () => {
+  const users = await TestUser.getInstances({
+    age: { $lt: 25 }
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('Charlie Wilson');
+});
+
+tap.test('should filter using $lte operator', async () => {
+  const users = await TestUser.getInstances({
+    age: { $lte: 25 }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Charlie Wilson', 'Jane Smith']);
+});
+
+tap.test('should filter using $ne operator', async () => {
+  const users = await TestUser.getInstances({
+    status: { $ne: 'active' }
+  });
+  expect(users.length).toEqual(2);
+  const statuses = users.map(u => u.status).sort();
+  expect(statuses).toEqual(['inactive', 'pending']);
+});
+
+tap.test('should filter using multiple comparison operators', async () => {
+  const users = await TestUser.getInstances({
+    age: { $gte: 25, $lt: 30 }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Alice Brown', 'Jane Smith']);
+});
+
+// ============= ARRAY OPERATOR TESTS =============
+tap.test('should filter using $in operator', async () => {
+  const users = await TestUser.getInstances({
+    status: { $in: ['active', 'pending'] }
+  });
+  expect(users.length).toEqual(4);
+  expect(users.every(u => ['active', 'pending'].includes(u.status))).toEqual(true);
+});
+
+tap.test('should filter arrays using $in operator', async () => {
+  const users = await TestUser.getInstances({
+    roles: { $in: ['admin'] }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Alice Brown', 'John Doe']);
+});
+
+tap.test('should filter using $nin operator', async () => {
+  const users = await TestUser.getInstances({
+    status: { $nin: ['inactive', 'pending'] }
+  });
+  expect(users.length).toEqual(3);
+  expect(users.every(u => u.status === 'active')).toEqual(true);
+});
+
+tap.test('should filter arrays using $all operator', async () => {
+  const users = await TestUser.getInstances({
+    tags: { $all: ['javascript', 'nodejs'] }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Bob Johnson', 'John Doe']);
+});
+
+tap.test('should filter arrays using $size operator', async () => {
+  const users = await TestUser.getInstances({
+    scores: { $size: 2 }
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('Charlie Wilson');
+});
+
+tap.test('should filter arrays using $elemMatch operator', async () => {
+  const orders = await TestOrder.getInstances({
+    items: {
+      $elemMatch: {
+        product: 'laptop',
+        quantity: { $gte: 2 }
+      }
+    }
+  });
+  expect(orders.length).toEqual(1);
+  expect(orders[0].totalAmount).toEqual(2560);
+});
+
+tap.test('should filter using $elemMatch with single condition', async () => {
+  const orders = await TestOrder.getInstances({
+    items: {
+      $elemMatch: {
+        price: { $gt: 100 }
+      }
+    }
+  });
+  expect(orders.length).toEqual(2);
+  expect(orders.every(o => o.items.some(i => i.price > 100))).toEqual(true);
+});
+
+// ============= LOGICAL OPERATOR TESTS =============
+tap.test('should filter using $or operator', async () => {
+  const users = await TestUser.getInstances({
+    $or: [
+      { age: { $lt: 25 } },
+      { status: 'inactive' }
+    ]
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Bob Johnson', 'Charlie Wilson']);
+});
+
+tap.test('should filter using $and operator', async () => {
+  const users = await TestUser.getInstances({
+    $and: [
+      { status: 'active' },
+      { age: { $gte: 28 } }
+    ]
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Alice Brown', 'John Doe']);
+});
+
+tap.test('should filter using $nor operator', async () => {
+  const users = await TestUser.getInstances({
+    $nor: [
+      { status: 'inactive' },
+      { age: { $lt: 25 } }
+    ]
+  });
+  expect(users.length).toEqual(3);
+  expect(users.every(u => u.status !== 'inactive' && u.age >= 25)).toEqual(true);
+});
+
+tap.test('should filter using nested logical operators', async () => {
+  const users = await TestUser.getInstances({
+    $or: [
+      {
+        $and: [
+          { status: 'active' },
+          { roles: { $in: ['admin'] } }
+        ]
+      },
+      { age: { $lt: 23 } }
+    ]
+  });
+  expect(users.length).toEqual(3);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Alice Brown', 'Charlie Wilson', 'John Doe']);
+});
+
+// ============= ELEMENT OPERATOR TESTS =============
+tap.test('should filter using $exists operator', async () => {
+  const users = await TestUser.getInstances({
+    'metadata.lastLogin': { $exists: true }
+  });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('John Doe');
+});
+
+tap.test('should filter using $exists false', async () => {
+  const users = await TestUser.getInstances({
+    'metadata.preferences': { $exists: false }
+  });
+  expect(users.length).toEqual(5);
+});
+
+// ============= COMPLEX FILTER TESTS =============
+tap.test('should handle complex nested filters', async () => {
+  const users = await TestUser.getInstances({
+    $and: [
+      { status: 'active' },
+      {
+        $or: [
+          { age: { $gte: 30 } },
+          { roles: { $all: ['admin'] } }
+        ]
+      },
+      { tags: { $in: ['mongodb'] } }
+    ]
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Alice Brown', 'John Doe']);
+});
+
+tap.test('should combine multiple operator types', async () => {
+  const orders = await TestOrder.getInstances({
+    $and: [
+      { totalAmount: { $gte: 100 } },
+      { status: { $in: ['completed', 'processing'] } },
+      { tags: { $in: ['electronics'] } }
+    ]
+  });
+  expect(orders.length).toEqual(2);
+  expect(orders.every(o => o.totalAmount >= 100)).toEqual(true);
+});
+
+// ============= ERROR HANDLING TESTS =============
+tap.test('should throw error for $where operator', async () => {
+  let error: Error | null = null;
+  try {
+    await TestUser.getInstances({
+      $where: 'this.age > 25'
+    });
+  } catch (e) {
+    error = e as Error;
+  }
+  expect(error).toBeTruthy();
+  expect(error?.message).toMatch(/\$where.*not allowed/);
+});
+
+tap.test('should throw error for invalid $in value', async () => {
+  let error: Error | null = null;
+  try {
+    await TestUser.getInstances({
+      status: { $in: 'active' as any } // Should be an array
+    });
+  } catch (e) {
+    error = e as Error;
+  }
+  expect(error).toBeTruthy();
+  expect(error?.message).toMatch(/\$in.*requires.*array/);
+});
+
+tap.test('should throw error for invalid $size value', async () => {
+  let error: Error | null = null;
+  try {
+    await TestUser.getInstances({
+      scores: { $size: '3' as any } // Should be a number
+    });
+  } catch (e) {
+    error = e as Error;
+  }
+  expect(error).toBeTruthy();
+  expect(error?.message).toMatch(/\$size.*requires.*numeric/);
+});
+
+tap.test('should throw error for dots in field names', async () => {
+  let error: Error | null = null;
+  try {
+    await TestUser.getInstances({
+      'some.nested.field': { 'invalid.key': 'value' }
+    });
+  } catch (e) {
+    error = e as Error;
+  }
+  expect(error).toBeTruthy();
+  expect(error?.message).toMatch(/keys cannot contain dots/);
+});
+
+// ============= EDGE CASE TESTS =============
+tap.test('should handle empty filter (return all)', async () => {
+  const users = await TestUser.getInstances({});
+  expect(users.length).toEqual(5);
+});
+
+tap.test('should handle null values in filter', async () => {
+  // First, create a user with null email
+  const nullUser = new TestUser({
+    name: 'Null User',
+    age: 40,
+    email: null as any,
+    roles: ['user'],
+    tags: [],
+    status: 'active',
+    metadata: {},
+    scores: []
+  });
+  await nullUser.save();
+
+  const users = await TestUser.getInstances({ email: null });
+  expect(users.length).toEqual(1);
+  expect(users[0].name).toEqual('Null User');
+
+  // Clean up
+  await nullUser.delete();
+});
+
+tap.test('should handle arrays as direct equality match', async () => {
+  // This tests that arrays without operators are treated as equality matches
+  const users = await TestUser.getInstances({
+    roles: ['user'] // Exact match for array
+  });
+  expect(users.length).toEqual(2);  // Both Jane and Charlie have exactly ['user']
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Charlie Wilson', 'Jane Smith']);
+});
+
+tap.test('should handle regex operator', async () => {
+  const users = await TestUser.getInstances({
+    name: { $regex: '^J', $options: 'i' }
+  });
+  expect(users.length).toEqual(2);
+  const names = users.map(u => u.name).sort();
+  expect(names).toEqual(['Jane Smith', 'John Doe']);
+});
+
+tap.test('should handle unknown operators by letting MongoDB reject them', async () => {
+  // Unknown operators should be passed through to MongoDB, which will reject them
+  let error: Error | null = null;
+  
+  try {
+    await TestUser.getInstances({
+      age: { $unknownOp: 30 } as any
+    });
+  } catch (e) {
+    error = e as Error;
+  }
+
+  expect(error).toBeTruthy();
+  expect(error?.message).toMatch(/unknown operator.*\$unknownOp/);
+});
+
+// ============= PERFORMANCE TESTS =============
+tap.test('should efficiently filter large result sets', async () => {
+  // Create many test documents
+  const manyUsers = [];
+  for (let i = 0; i < 100; i++) {
+    manyUsers.push(new TestUser({
+      name: `User ${i}`,
+      age: 20 + (i % 40),
+      email: `user${i}@example.com`,
+      roles: i % 3 === 0 ? ['admin'] : ['user'],
+      tags: i % 2 === 0 ? ['even', 'test'] : ['odd', 'test'],
+      status: i % 4 === 0 ? 'inactive' : 'active',
+      metadata: { loginCount: i },
+      scores: [i, i + 10, i + 20]
+    }));
+  }
+
+  // Save in batches for efficiency
+  for (const user of manyUsers) {
+    await user.save();
+  }
+
+  // Complex filter that should still be fast
+  const startTime = Date.now();
+  const filtered = await TestUser.getInstances({
+    $and: [
+      { age: { $gte: 30, $lt: 40 } },
+      { status: 'active' },
+      { tags: { $in: ['even'] } },
+      { 'metadata.loginCount': { $gte: 20 } }
+    ]
+  });
+  const duration = Date.now() - startTime;
+
+  console.log(`Complex filter on 100+ documents took ${duration}ms`);
+  expect(duration).toBeLessThan(1000); // Should complete in under 1 second
+  expect(filtered.length).toBeGreaterThan(0);
+
+  // Clean up
+  for (const user of manyUsers) {
+    await user.delete();
+  }
+});
+
+// ============= CLEANUP =============
+tap.test('should clean up test database', async () => {
+  await testDb.mongoDb.dropDatabase();
+  await testDb.close();
+  await smartmongoInstance.stop();
+});
+
+export default tap.start();

ts/classes.doc.ts

@@ -151,9 +151,49 @@ export function index(options?: IIndexOptions) {
   };
 }
 
+// Type that allows MongoDB operators on leaf values while maintaining nested type safety
+export type MongoFilterCondition<T> = T | {
+  $eq?: T;
+  $ne?: T;
+  $gt?: T;
+  $gte?: T;
+  $lt?: T;
+  $lte?: T;
+  $in?: T extends (infer U)[] ? U[] | U : T[];
+  $nin?: T extends (infer U)[] ? U[] | U : T[];
+  $exists?: boolean;
+  $type?: string | number;
+  $regex?: string | RegExp;
+  $options?: string;
+  $all?: T extends (infer U)[] ? U[] : never;
+  $elemMatch?: T extends (infer U)[] ? MongoFilter<U> : never;
+  $size?: T extends any[] ? number : never;
+  $not?: MongoFilterCondition<T>;
+};
+
+export type MongoFilter<T> = {
+  [K in keyof T]?: T[K] extends object 
+    ? T[K] extends any[]
+      ? MongoFilterCondition<T[K]>  // Arrays can have operators
+      : MongoFilter<T[K]> | MongoFilterCondition<T[K]>  // Objects can be nested or have operators
+    : MongoFilterCondition<T[K]>;  // Primitives get operators
+} & {
+  // Logical operators
+  $and?: MongoFilter<T>[];
+  $or?: MongoFilter<T>[];
+  $nor?: MongoFilter<T>[];
+  $not?: MongoFilter<T>;
+  // Allow any string key for dot notation (we lose type safety here but maintain flexibility)
+  [key: string]: any;
+};
+
 export const convertFilterForMongoDb = (filterArg: { [key: string]: any }) => {
+  // SECURITY: Block $where to prevent server-side JS execution
+  if (filterArg.$where !== undefined) {
+    throw new Error('$where operator is not allowed for security reasons');
+  }
+  
   // Special case: detect MongoDB operators and pass them through directly
-  // SECURITY: Removed $where to prevent server-side JS execution
   const topLevelOperators = ['$and', '$or', '$nor', '$not', '$text', '$regex'];
   for (const key of Object.keys(filterArg)) {
     if (topLevelOperators.includes(key)) {
@@ -166,26 +206,76 @@ export const convertFilterForMongoDb = (filterArg: { [key: string]: any }) => {
 
   const convertFilterArgument = (keyPathArg2: string, filterArg2: any) => {
     if (Array.isArray(filterArg2)) {
-      // FIX: Properly handle arrays for operators like $in, $all, or plain equality
+      // Arrays are typically used as values for operators like $in or as direct equality matches
       convertedFilter[keyPathArg2] = filterArg2;
       return;
     } else if (typeof filterArg2 === 'object' && filterArg2 !== null) {
-      for (const key of Object.keys(filterArg2)) {
+      // Check if this is an object with MongoDB operators
-        if (key.startsWith('$')) {
+      const keys = Object.keys(filterArg2);
-          // Prevent dangerous operators
+      const hasOperators = keys.some(key => key.startsWith('$'));
-          if (key === '$where') {
+      
-            throw new Error('$where operator is not allowed for security reasons');
+      if (hasOperators) {
-          }
+        // This object contains MongoDB operators
-          convertedFilter[keyPathArg2] = filterArg2;
+        // Validate and pass through allowed operators
-          return;
+        const allowedOperators = [
-        } else if (key.includes('.')) {
+          // Comparison operators
+          '$eq', '$ne', '$gt', '$gte', '$lt', '$lte',
+          // Array operators
+          '$in', '$nin', '$all', '$elemMatch', '$size',
+          // Element operators
+          '$exists', '$type',
+          // Evaluation operators (safe ones only)
+          '$regex', '$options', '$text', '$mod',
+          // Logical operators (nested)
+          '$and', '$or', '$nor', '$not'
+        ];
+        
+        // Check for dangerous operators
+        if (keys.includes('$where')) {
+          throw new Error('$where operator is not allowed for security reasons');
+        }
+        
+        // Validate all operators are in the allowed list
+        const invalidOperators = keys.filter(key => 
+          key.startsWith('$') && !allowedOperators.includes(key)
+        );
+        
+        if (invalidOperators.length > 0) {
+          console.warn(`Warning: Unknown MongoDB operators detected: ${invalidOperators.join(', ')}`);
+        }
+        
+        // For array operators, ensure the values are appropriate
+        if (filterArg2.$in && !Array.isArray(filterArg2.$in)) {
+          throw new Error('$in operator requires an array value');
+        }
+        if (filterArg2.$nin && !Array.isArray(filterArg2.$nin)) {
+          throw new Error('$nin operator requires an array value');
+        }
+        if (filterArg2.$all && !Array.isArray(filterArg2.$all)) {
+          throw new Error('$all operator requires an array value');
+        }
+        if (filterArg2.$size && typeof filterArg2.$size !== 'number') {
+          throw new Error('$size operator requires a numeric value');
+        }
+        
+        // Pass the operator object through
+        convertedFilter[keyPathArg2] = filterArg2;
+        return;
+      }
+      
+      // No operators, check for dots in keys
+      for (const key of keys) {
+        if (key.includes('.')) {
           throw new Error('keys cannot contain dots');
         }
       }
-      for (const key of Object.keys(filterArg2)) {
+      
+      // Recursively process nested objects
+      for (const key of keys) {
         convertFilterArgument(`${keyPathArg2}.${key}`, filterArg2[key]);
       }
     } else {
+      // Primitive values
       convertedFilter[keyPathArg2] = filterArg2;
     }
   };
@@ -227,12 +317,12 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
   /**
    * gets all instances as array
    * @param this
-   * @param filterArg
+   * @param filterArg - Type-safe MongoDB filter with nested object support and operators
    * @returns
    */
   public static async getInstances<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
+    filterArg: MongoFilter<T>,
     opts?: { session?: plugins.mongodb.ClientSession }
   ): Promise<T[]> {
     // Pass session through to findAll for transactional queries
@@ -256,7 +346,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
    */
   public static async getInstance<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
+    filterArg: MongoFilter<T>,
     opts?: { session?: plugins.mongodb.ClientSession }
   ): Promise<T> {
     // Retrieve one document, with optional session for transactions
@@ -289,7 +379,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
    */
   public static async getCursor<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
+    filterArg: MongoFilter<T>,
     opts?: {
       session?: plugins.mongodb.ClientSession;
       modifier?: (cursorArg: plugins.mongodb.FindCursor<plugins.mongodb.WithId<plugins.mongodb.BSON.Document>>) => plugins.mongodb.FindCursor<plugins.mongodb.WithId<plugins.mongodb.BSON.Document>>;
@@ -319,7 +409,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
    */
   public static async watch<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
+    filterArg: MongoFilter<T>,
     opts?: plugins.mongodb.ChangeStreamOptions & { bufferTimeMs?: number },
   ): Promise<SmartdataDbWatcher<T>> {
     const collection: SmartdataCollection<T> = (this as any).collection;
@@ -337,7 +427,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
    */
   public static async forEach<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T>,
+    filterArg: MongoFilter<T>,
     forEachFunction: (itemArg: T) => Promise<any>,
   ) {
     const cursor: SmartdataDbCursor<T> = await (this as any).getCursor(filterArg);
@@ -349,7 +439,7 @@ export class SmartDataDbDoc<T extends TImplements, TImplements, TManager extends
    */
   public static async getCount<T>(
     this: plugins.tsclass.typeFest.Class<T>,
-    filterArg: plugins.tsclass.typeFest.PartialDeep<T> = {} as any,
+    filterArg: MongoFilter<T> = {} as any,
   ) {
     const collection: SmartdataCollection<T> = (this as any).collection;
     return await collection.getCount(filterArg);