TinyBase

addRowListener

The addRowListener method registers a listener function with the Store that will be called whenever data in a Row changes.

addRowListener(
  tableId: IdOrNull,
  rowId: IdOrNull,
  listener: RowListener,
  mutator?: boolean,
): string
TypeDescription
tableIdIdOrNull

The Id of the Table to listen to, or null as a wildcard.

rowIdIdOrNull

The Id of the Row to listen to, or null as a wildcard.

listenerRowListener

The function that will be called whenever data in the matching Row changes.

mutator?boolean

An optional boolean that indicates that the listener mutates Store data.

returnsstring

A unique Id for the listener that can later be used to call it explicitly, or to remove it.

You can either listen to a single Row (by specifying the Table Id and Row Id as the method's first two parameters) or changes to any Row (by providing null wildcards).

Both, either, or neither of the tableId and rowId parameters can be wildcarded with null. You can listen to a specific Row in a specific Table, any Row in a specific Table, a specific Row in any Table, or any Row in any Table.

The provided listener is a RowListener function, and will be called with a reference to the Store, the Id of the Table that changed, the Id of the Row that changed, and a GetCellChange function in case you need to inspect any changes that occurred.

Use the optional mutator parameter to indicate that there is code in the listener that will mutate Store data. If set to false (or omitted), such mutations will be silently ignored. All relevant mutator listeners (with this flag set to true) are called before any non-mutator listeners (since the latter may become relevant due to changes made in the former). The changes made by mutator listeners do not fire other mutating listeners, though they will fire non-mutator listeners.

Examples

This example registers a listener that responds to any changes to a specific Row.

const store = createStore().setTables({
  pets: {fido: {species: 'dog', color: 'brown'}},
});
const listenerId = store.addRowListener(
  'pets',
  'fido',
  (store, tableId, rowId, getCellChange) => {
    console.log('fido row in pets table changed');
    console.log(getCellChange('pets', 'fido', 'color'));
  },
);

store.setCell('pets', 'fido', 'color', 'walnut');
// -> 'fido row in pets table changed'
// -> [true, 'brown', 'walnut']

store.delListener(listenerId);

This example registers a listener that responds to any changes to any Row.

const store = createStore().setTables({
  pets: {fido: {species: 'dog', color: 'brown'}},
});
const listenerId = store.addRowListener(
  null,
  null,
  (store, tableId, rowId) => {
    console.log(`${rowId} row in ${tableId} table changed`);
  },
);

store.setCell('pets', 'fido', 'color', 'walnut');
// -> 'fido row in pets table changed'
store.setTable('species', {dog: {price: 5}});
// -> 'dog row in species table changed'

store.delListener(listenerId);

This example registers a listener that responds to any changes to a specific Row, and which also mutates the Store itself.

const store = createStore().setTables({
  pets: {fido: {species: 'dog', color: 'brown'}},
});
const listenerId = store.addRowListener(
  'pets',
  'fido',
  (store, tableId, rowId) =>
    store.setCell('meta', 'update', `${tableId}_${rowId}`, true),
  true,
);

store.delCell('pets', 'fido', 'color');
console.log(store.getTable('meta'));
// -> {update: {pets_fido: true}}

store.delListener(listenerId);