1/* 2 * Copyright (c) 2024 Huawei Device Co., Ltd. 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 */ 15 16class A { 17 status: string = ""; 18} 19 20class B { 21 status: string = ""; 22} 23 24type Union = A | B; 25 26function main() : void { 27 let fn = (value : Union) : string => { 28 return value.status; 29 }; 30 31 let a : A = new A(); 32 let b : B = new B(); 33 a.status = "hello_a"; 34 b.status = "hello_b"; 35 assert fn(a) === "hello_a"; 36 assert fn(b) === "hello_b"; 37} 38