HarmonyOS 鸿蒙Next NAPI能否导出一个class 封装多个方法

declare namespace testNapi {
    const add: (a: number, b: number) => number;
    const sub: (a: number, b: number) => number;
    const getString: (a: string) => string;
    // 定义js接口
    class MyDemo {
        constructor(name: string)
        name: string

        add(a: number, b: number): number
        sub(a: number, b: number): number
    }
}

export default testNapi;

import hilog from '@ohos.hilog';
import testNapi from 'liblibrary.so';

@Component
export struct MainPage {
    @State message: string = 'Hello World';

    build() {
        Row() {
            Column() {
                Text(this.message)
                    .fontSize(50)
                    .fontWeight(FontWeight.Bold)
                    .onClick(() => {
                        new testNapi.MyDemo('abc');
                        hilog.info(0x0000, 'testTag', 'Test NAPI 2 + 3 = %{public}d', testNapi.add(2, 3));
                        hilog.info(0x0000, 'testTag', 'Test NAPI 2 + 3 = %{public}d', testNapi.sub(2, 3));
                    })
            }
        .width('100%')
        }
    .height('100%')
    }
}