render() { return ( <App header = {CheckboxesStore.header} items = {CheckboxesStore.items} changeItems = {(label, checked) => transaction(() => CheckboxesStore.items.forEach((itemChecked, itemLabel) => CheckboxesStore.items.get(itemLabel).checked = checked))} changeItem = {(label, checked) => CheckboxesStore.items.get(label).checked = checked} /> ); }