import { Expression } from '../../core/expression';
import { PipeOperator } from '../../core/pipe-operator';
import { DataType } from '../../types/data-type';
export declare class FieldOperator implements PipeOperator {
    readonly name: string;
    private readonly type;
    constructor(name: string, type?: DataType);
    instantiate(input: Expression): Expression<any>;
    private apply;
    private applyWithoutKnownType;
}
export declare function field<TIn, TField extends keyof NonNullable<TIn> & string>(name: TField): PipeOperator<TIn, undefined extends TIn ? NonNullable<TIn>[TField] | undefined : NonNullable<TIn>[TField]>;