import { QueryHookPlugin, QueryResultContext } from '../index';
/**
 * Transformer function type
 */
export type TransformerFn<T = any, R = any> = (data: T, context: QueryResultContext) => R | Promise<R>;
/**
 * Options for QueryResultTransformerPlugin
 */
export interface QueryResultTransformerOptions {
    /**
     * Transformers by entity/table name
     * Maps table name to transformer function
     *
     * @example
     * ```typescript
     * {
     *   User: (user) => ({
     *     ...user,
     *     fullName: `${user.firstName} ${user.lastName}`,
     *     password: undefined // Remove sensitive data
     *   })
     * }
     * ```
     */
    transformers?: Record<string, TransformerFn>;
    /**
     * Global transformer applied to all results (optional)
     * Runs before entity-specific transformers
     */
    globalTransformer?: TransformerFn;
    /**
     * Callback when a result is transformed (optional)
     * Triggered after transformation is complete
     *
     * @param context - Query result context
     * @param originalResult - Result before transformation
     * @param transformedResult - Result after transformation
     *
     * @example
     * ```typescript
     * onTransformed: (context, originalResult, transformedResult) => {
     *   logger.info('Result transformed', {
     *     tables: extractTablesFromBuilder(context.builder),
     *     originalType: typeof originalResult,
     *     transformedType: typeof transformedResult
     *   });
     * }
     * ```
     */
    onTransformed?: (context: QueryResultContext, originalResult: any, transformedResult: any) => void;
    /**
     * Callback when transformation fails (optional)
     *
     * @param context - Query result context
     * @param error - The error that occurred
     *
     * @example
     * ```typescript
     * onError: (context, error) => {
     *   logger.error('Result transformation failed', {
     *     error,
     *     tables: extractTablesFromBuilder(context.builder)
     *   });
     * }
     * ```
     */
    onError?: (context: QueryResultContext, error: Error) => void;
    /**
     * Enable console logging for this plugin (default: false)
     */
    enableLogging?: boolean;
}
/**
 * Plugin for transforming query results
 * Automatically converts DB results to DTOs/view models
 *
 * 🔄 Solves: Manual transformation of database results to DTOs
 *
 * **Common Use Cases:**
 * 1. Remove sensitive fields (passwords, tokens)
 * 2. Combine fields (firstName + lastName = fullName)
 * 3. Format dates, numbers
 * 4. Add computed properties
 * 5. Flatten nested objects
 *
 * @example
 * ```typescript
 * import { QueryResultTransformerPlugin } from 'typeorm-query-hooks/plugins/query-result-transformer';
 *
 * registerPlugin(QueryResultTransformerPlugin({
 *   transformers: {
 *     User: (user) => ({
 *       id: user.id,
 *       fullName: `${user.firstName} ${user.lastName}`,
 *       email: user.email,
 *       // Remove sensitive data
 *       password: undefined,
 *       resetToken: undefined
 *     }),
 *     Product: (product) => ({
 *       ...product,
 *       price: `$${product.price.toFixed(2)}`,
 *       inStock: product.quantity > 0
 *     })
 *   },
 *   globalTransformer: (result) => {
 *     // Add metadata to all results
 *     if (Array.isArray(result)) {
 *       return {
 *         data: result,
 *         count: result.length,
 *         timestamp: new Date()
 *       };
 *     }
 *     return result;
 *   },
 *   enableLogging: true
 * }));
 * ```
 */
export declare function QueryResultTransformerPlugin(options: QueryResultTransformerOptions): QueryHookPlugin;
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