import { StateOperator } from '@ngxs/store';
import { RepairType } from './utils';
import { Predicate } from './internals';
/**
 * @param selector - Index of item in the array or a predicate function
 * that can be provided in `Array.prototype.findIndex`
 * @param operatorOrValue - New value under the `selector` index or a
 * function that can be applied to an existing value
 */
export declare function updateItem<T>(selector: number | Predicate<T>, operatorOrValue: T | StateOperator<T>): StateOperator<RepairType<T>[]>;