充分利用TypeScript实用工具类型

1type User = {
2  id: number;
3  name: string;
4  email: string;
5};

1function updateUser(user: User, updates: Partial<User>) {
2  return { ...user, ...updates };
3}
4
5// 使用示例
6const user: User = { id: 1, name: '小明', email: 'xiaoming@example.com' };
7const updatedUser = updateUser(user, { name: '小华' });

1type Config = {
2  apiEndpoint: string;
3  timeout: number;
4};
5
6const config: Readonly<Config> = {
7  apiEndpoint: 'https://api.example.com',
8  timeout: 5000,
9};
10
11// 错误：无法分配到 'timeout' ，因为它是只读属性
12config.timeout = 3000;

1type User = {
2  id: number;
3  name: string;
4  email: string;
5  address: string;
6};
7
8type UserSummary = Pick<User, 'id' | 'name'>;
9
10const userSummary: UserSummary = {
11  id: 1,
12  name: '小明',
13};
14
15// 错误：类型'UserSummary'上不存在属性'email'
16userSummary.email = 'xiaoming@example.com';

1type UserWithoutAddress = Omit<User, 'address'>;
2
3const userWithoutAddress: UserWithoutAddress = {
4  id: 1,
5  name: '小明',
6  email: 'xiaoming@example.com',
7};
8
9// 错误：类型'UserWithoutAddress'上不存在属性'address'
10userWithoutAddress.address = '北京市朝阳区';

1type Role = 'admin' | 'user' | 'guest';
2type Permissions = 'read' | 'write' | 'delete';
3
4const rolePermissions: Record<Role, Permissions[]> = {
5  admin: ['read', 'write', 'delete'],
6  user: ['read', 'write'],
7  guest: ['read'],
8};

1type Status = 'active' | 'inactive' | 'suspended';
2
3type ActiveStatus = Exclude<Status, 'suspended'>;
4
5const status: ActiveStatus = 'active'; // 有效
6const anotherStatus: ActiveStatus = 'suspended'; // 错误