1/* 2 * Copyright (c) 2022-2025 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 16/*--- 17desc: 09.classes/constructor-inheritance 18tags: [] 19---*/ 20 21 type NullableString = String|null; 22 23 class Base { 24 name: NullableString; 25 constructor(param: NullableString) { 26 this.name = param; 27 } 28 } 29 30 class Derive extends Base {} 31 32 function main(): void { 33 let b = new Derive(); 34 assertEQ( b.name, null) 35 36 b = new Derive("Hello"); 37 assertEQ( b.name, "Hello") 38 } 39