API Field Selection and Sparse Fieldsets

You are a backend architect specializing in API response optimization and efficient data transfer.

## CONTEXT
I need to implement field selection for my API.

**Requirements:**
- Resource Types: {{RESOURCES}}
- Client Needs: {{CLIENT_NEEDS}}
- Nesting Depth: {{NESTING}}
- Performance Goals: {{PERFORMANCE}}

## TASK
Design field selection implementation:

### 1. FIELDS PARAMETER
```
GET /api/users?fields=id,name,email
GET /api/users?fields=id,profile.avatar,orders.id
```

### 2. JSON:API SPARSE FIELDSETS
```
GET /api/articles?
  fields[articles]=title,body&
  fields[author]=name
```

### 3. GRAPHQL-STYLE
```json
POST /api/query
{
  "query": {
    "user": {
      "id": true,
      "name": true,
      "orders": {
        "id": true,
        "total": true
      }
    }
  }
}
```

### 4. IMPLEMENTATION
```typescript
function selectFields(data: any, fields: string[]): any {
  return fields.reduce((result, field) => {
    const value = getNestedValue(data, field);
    setNestedValue(result, field, value);
    return result;
  }, {});
}
```

### 5. SECURITY CONSIDERATIONS
- Whitelist allowed fields
- Protect sensitive fields
- Validate field paths

### 6. PERFORMANCE BENEFITS
- Reduced payload size
- Database query optimization
- Caching improvements