@tanstack/db/dist/esm/collection/change-events.d.ts

A reactive client store for building super fast apps on sync

import { ChangeMessage, CollectionLike, CurrentStateAsChangesOptions, SubscribeChangesOptions } from '../types.js';
import { BasicExpression } from '../query/ir.js';
import { WithVirtualProps } from '../virtual-props.js';
/**
 * Yields visible entries, enriched with virtual properties, whose stored row
 * passes `prefilter`.
 */
export type StoredRowScan<T extends object, TKey extends string | number> = (prefilter: (row: object) => boolean) => Iterable<[TKey, WithVirtualProps<T, TKey>]>;
/**
 * A test on a stored row that is false only when `expression` must be false
 * on the row's enriched copy, so a scan can skip enriching rows that fail.
 * It reads one `eq(field, literal)` conjunct. The copy holds each enumerable
 * own root field of the stored row and lacks the others, so its field is the
 * stored value or `undefined`, which matches no literal.
 */
export declare function compileStoredRowPrefilter(expression: BasicExpression<boolean>): ((row: object) => boolean) | undefined;
/**
 * Returns the current state of the collection as an array of changes
 * @param collection - The collection to get changes from
 * @param options - Options including optional where filter, orderBy, and limit
 * @returns An array of changes
 * @example
 * // Get all items as changes
 * const allChanges = currentStateAsChanges(collection)
 *
 * // Get only items matching a condition
 * const activeChanges = currentStateAsChanges(collection, {
 *   where: (row) => row.status === 'active'
 * })
 *
 * // Get only items using a pre-compiled expression
 * const activeChanges = currentStateAsChanges(collection, {
 *   where: eq(row.status, 'active')
 * })
 *
 * // Get items ordered by name with limit
 * const topUsers = currentStateAsChanges(collection, {
 *   orderBy: [{ expression: row.name, compareOptions: { direction: 'asc' } }],
 *   limit: 10
 * })
 *
 * // Get active users ordered by score (highest score first)
 * const topActiveUsers = currentStateAsChanges(collection, {
 *   where: eq(row.status, 'active'),
 *   orderBy: [{ expression: row.score, compareOptions: { direction: 'desc' } }],
 * })
 */
export declare function currentStateAsChanges<T extends object, TKey extends string | number>(collection: CollectionLike<WithVirtualProps<T, TKey>, TKey>, options?: CurrentStateAsChangesOptions, scanStoredRows?: StoredRowScan<T, TKey>): Array<ChangeMessage<WithVirtualProps<T, TKey>, TKey>> | void;
/**
 * Creates a filter function from a pre-compiled expression
 * @param expression - The pre-compiled expression to evaluate
 * @returns A function that takes an item and returns true if it matches the filter
 */
export declare function createFilterFunctionFromExpression<T extends object>(expression: BasicExpression<boolean>): (item: T) => boolean;
/**
 * Creates a filtered callback that only calls the original callback with changes that match the where clause
 * @param originalCallback - The original callback to filter
 * @param options - The subscription options containing the where clause
 * @returns A filtered callback function
 */
export declare function createFilteredCallback<T extends object, TKey extends string | number = string | number>(originalCallback: (changes: Array<ChangeMessage<T>>) => void, options: SubscribeChangesOptions<T, TKey>): (changes: Array<ChangeMessage<T>>) => boolean;