Property decorators are generally not used alone, but are mainly used in combination with class or method decorators for composite decoration.

## Parameters

*   The property decorator function has two parameters: **target**

    *   For regular properties, *target* is the prototype of the current object. In other words, if *Employee* is an object, then *target* is `Employee.prototype`.

    *   For static properties, *target* is the class of the current object.

**propertyKey**

```typescript
const userRoles: string[] = [];

// Assign the role to userRoles through property decorators.
const RoleDecorator = (roles: string[]) => (target: any, key: string) => {
    roles.forEach((role) => userRoles.push(role));
};

// Generate a Roles object based on userRoles and assign it to the roles property of the class prototype.
const SetRoleDecorator = <
    T extends new (...args: any[]) => {
        [key: string]: any;
    },
    >(
    constructor: T,
) => {
    const roles = [
        { name: 'super-admin', desc: 'Super administrator' },
        { name: 'admin', desc: 'Administrator' },
        { name: 'user', desc: 'Client' },
    ];
    return class extends constructor {
        constructor(...args: any) {
            super(...args);
            this.roles = roles.filter((role) => userRoles.includes(role.name));
        }
    };
};

@SetRoleDecorator
class UserEntity {
    @RoleDecorator(['admin', 'user'])
    roles: string[] = [];
}

export const exp5 = () => {
    console.log();
    console.log(
        '-----------------------Property decorator-----------------------',
    );
    console.log(
        '-----------------------Filter user list based on permissions using decorators.--------------------',
    );
    console.log();
    const user = new UserEntity();
    console.log(user.roles);
    console.log();
    console.log('-----------------------End-----------------------');
};

// console [ { name: 'admin', desc: 'Administrator' }, { name: 'user', desc: 'Client' } ]
```


3. Property Decorator

Property decorators are generally not used alone, but are mainly used in combination with class or...