给MyTest.ts尽量标注全部类型，并通过检查解构结果result是否为真值，避免将undefined分配给{ name: string, age: number }的类型 function getInputSomething(): string { return '1341534'; } function loadFromDatabase(id: number): { id: number, name: string, age: number } | undefined { if (isNaN(id)) return; // .... load from database return { id, name: '张三', age: 25 }; } let s: string = getInputSomething(); let id: number = parseInt(s); let result = loadFromDatabase(id); if (result) { let { name, age } = result; console.log(name, age); } else { console.log('Data not found'); }