$strict

Strict flag. If set, throw error if found not defined properties.

**Example**
```js
let schema = {
    $strict: true,
    name: { type: "string" }
}

v.validate({
    name: "John"
}, schema);
// Valid

v.validate({
    name: "John",
    age: 30,
}, schema);
// Error because 'age' property is not allowed.
```