Adds optional callback to `setState`

This commit adds an optional callback as a second argument to `setState`, to be called after `setState` runs. We never guarantee synchronous execution of `setState`, and as per @phunt, we don't want to make that guarantee because we may eventually batch calls to `setState`. @jwalke agrees with him.

ngavalas committed Jun 14, 2013 at 16:23 UTC c6665e346030f73b7ebb615ce1affe8396b0dab8

1 file changed +9 -1

src/core/ReactCompositeComponent.js

+9 -1

@@ -525,13 +525,21 @@ var ReactCompositeComponentMixin = {

525 * There is no guarantee that `this.state` will be immediately updated, so

526 * accessing `this.state` after calling this method may return the old value.

527 *

528 + * There is no guarantee that calls to `setState` will run synchronously,

529 + * as they may eventually be batched together. You can provide an optional

530 + * callback that will be executed when the call to setState is actually

531 + * completed.

532 + *

533 * @param {object} partialState Next partial state to be merged with state.

534 + * @param {?function} callback Called after state is updated.

535 * @final

536 * @protected

537 */

532 - setState: function(partialState) {

538 + setState: function(partialState, callback) {

539 // Merge with `_pendingState` if it exists, otherwise with existing state.

540 this.replaceState(merge(this._pendingState || this.state, partialState));

541 + // If `callback` is callable, do it.

542 + typeof callback === 'function' && callback();

543 },

544

545 /**