import type { DeepPartial } from './util';
/**
  Shortcut function
  Replace only fields from [keys] arg in {a} with {b}

  ex: (['b'], { a: 0, b: 0 }, { a: 1, b: 1 }) -> { a: 0, b: 1 }
*/
export declare function mergeLeftOnly<T extends Record<string, any>>(keys: Array<keyof T>, source: T, target?: DeepPartial<T>): T;