TxDataSource · Flutter

Observable data source with query state and asynchronous loading. Writes reload the data; its owner disposes the instance.

Default configuration: pageSize 20, pageIndex 0, paginate true; array stores are local, other stores remote. The Vue array shorthand retains paging; Dart TxDataSource.array defaults to paginate false. items starts empty; call load() unless a bound consumer triggers the initial load. Invalid paging is rejected. Replace the store and key by creating a new instance. configure returns a Promise/Future of the reloaded list. byKey returns a Promise/Future of a record or undefined/null; insert/update return the written record and remove returns no value. Vue push returns the new list; Dart push returns no value. cancel/dispose return no value. Load/write failures are also exposed in error. For unsupported operations Vue throws Error and Dart throws UnsupportedError. Loading after disposal fails.

TxDataSource

Parameter	Type	Default	Meaning
config	`TxDataSourceConfig<T>`	`required`	Instance configuration.

TxDataSource.array

Parameter	Type	Default	Meaning
items	`List<T>`	`required`	Entries; replaced by dataSource when bound.
keyOf	`TxKeyOf<T>?`	`null`	Reads the stable record key.
paginate	`bool`	`false`	Enables paging; false loads the whole collection.

Member / type / return	Meaning
`TxStore<T> get store`	Data collection or custom store contract.
`List<T> get items`	Entries; replaced by dataSource when bound.
`List<TxGroup<T>> groups = []`	Result group hierarchy.
`int totalCount = 0`	Total filtered record count before paging.
`int revision = 0`	Revision counter after a successful load.
`bool? containsKey(Object key)`	Returns false for known removals, a boolean for an array store, otherwise undefined/null.
`int? groupCount`	Top-level group count before paging.
`bool loading = false`	Shows the loading state.
`bool loaded = false`	At least one load completed successfully.
`Object? error`	Most recent load/write error.
`List<TxSort<T>> sort`	Sort descriptors in priority order.
`List<TxSort<T>> group`	Group descriptors or group name.
`TxFilter<T>? filter`	Filter expression.
`List<TxGetter<T>> searchExpr`	Search fields or getters.
`String searchValue`	Search text; local search ignores case.
`int pageSize`	Records per page.
`int pageIndex`	Zero-based page index.
`Future<List<T>> load()`	Loads using the supplied options; DataSource uses current query state without arguments. Errors propagate.
`Future<List<T>> reload()`	Reloads the current query and returns visible records.
`Future<List<T>> configure({List<TxSort<T>>? sort, TxFilter<T>? filter, bool clearFilter = false, String? searchValue, List<TxGetter<T>>? searchExpr, List<TxSort<T>>? group, int? pageSize, int? pageIndex})`	Changes query options and reloads. Search, filter and page size reset the page unless explicitly supplied.
`void cancel()`	Set synchronously to true to cancel the action.
`Future<T?> byKey(Object key)`	Reads a record by key; missing keys return undefined (Vue) or null (Dart).
`Future<T> insert(T item)`	Inserts a record with a unique key and returns it.
`Future<T> update(Object key, T Function(T) change)`	Updates a notification or record.
`Future<void> remove(Object key)`	Removes the record or recursively removes a file/directory tree.
`Future<void> push(List<TxPush<T>> changes)`	Runs store writes sequentially and reloads once; not a transaction, partial success is possible on error.
`void dispose()`	Stops queries and listeners; do not use the instance afterward.

dart

import 'package:flutter/material.dart';
import 'package:tecexpress/tecexpress.dart';

Future<void> example() async {
  final source = TxDataSource.array(<Map<String, Object>>[{'id': 1, 'name': 'One'}], keyOf: (row) => row['id']!);
  void listener() => debugPrint('${source.loading}: ${source.error}');
  source.addListener(listener);
  await source.load();
  await source.configure(searchExpr: [(row) => row['name']], searchValue: 'One');
  await source.insert({'id': 2, 'name': 'Two'});
  await source.update(2, (row) => {...row, 'name': 'Updated'});
  await source.push([TxPush.update(2, (row) => {...row, 'name': 'Changed'})]);
  print(await source.byKey(1));
  print(source.containsKey(1));
  await source.remove(2);
  await source.reload();
  source.cancel();
  source.removeListener(listener);
  source.dispose();
}