interface Item {
    id: number;
    name: string;
    age: number;
}

const form: Item = {
    id: 99,
    name: 'k',
    age: 99,
};

const text: Item = {
    id: 1,
    name: '张三',
    age: 18,
};

(['id','name','age'] as const).forEach(key => {
    text[key] = text[key];
});

// Type 'string | number' is not assignable to type 'never'.
// Type 'string' is not assignable to type 'never'.