json解析对象后获取数据返回undefined。

let serialId3:Record<string, number | string> = {'serialId3':'11111111122222222'};

@Entry 
@Component 
struct Test { 
  build() { 
    Column() { 
      Button('获取serialId3').onClick((event: ClickEvent) => { 
        test() 
      }) 
    } 
  } 
} 
 
function test() { 
  //let serialId3 = "{'serialId3':'11111111122222222'}"; 
  let serialId3: Record<string, number | string> = { 'serialId3': 'PWLYD22415400154' }; 
  let ser: KeyboardMessage = JSON.parse(JSON.stringify(serialId3)); 
  console.info(ser.serialId3); 
} 
 
export interface KeyboardMessage { 
  serialId3: string; 
}