1// Copyright (C) 2022 The Android Open Source Project 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14 15import {Selection} from './state'; 16 17export type SelectionChangedObserver = 18 (newSelection?: Selection, oldSelection?: Selection) => void; 19 20const selectionObservers: SelectionChangedObserver[] = []; 21 22export function onSelectionChanged( 23 newSelection?: Selection, oldSelection?: Selection) { 24 for (const observer of selectionObservers) { 25 observer(newSelection, oldSelection); 26 } 27} 28 29export function addSelectionChangeObserver(observer: SelectionChangedObserver): 30 void { 31 selectionObservers.push(observer); 32} 33