类型安全的配置系统

1. 配置类型定义

interface AppConfig {
  api: {
    baseURL: string;
    timeout: number;
    retries: number;
  };
  features: {
    darkMode: boolean;
    analytics: boolean;
    notifications: boolean;
  };
  version: string;
}

type ConfigPath = `api.${string}` | `features.${string}` | 'version';

2. 类型安全的配置访问

type DeepGet<T, P extends string> = P extends `${infer K}.${infer Rest}`
  ? K extends keyof T
    ? DeepGet<T[K], Rest>
    : never
  : P extends keyof T
    ? T[P]
    : never;

class ConfigManager<T> {
  constructor(private config: T) {}

  get<P extends string>(path: P): DeepGet<T, P> {
    return path.split('.').reduce((obj: any, key) => obj?.[key], this.config);
  }

  set<P extends string>(path: P, value: DeepGet<T, P>): void {
    const keys = path.split('.');
    const last = keys.pop()!;
    const target = keys.reduce((obj: any, key) => obj[key], this.config);
    target[last] = value;
  }
}

const config = new ConfigManager<AppConfig>({
  api: { baseURL: 'https://api.example.com', timeout: 5000, retries: 3 },
  features: { darkMode: true, analytics: false, notifications: true },
  version: '1.0.0',
});

config.get('api.baseURL'); // string
config.get('features.darkMode'); // boolean