nupst/ts/migrations/base-migration.ts

/**
 * Abstract base class for configuration migrations
 *
 * Each migration represents an upgrade from one config version to another.
 * Migrations run in order based on the `order` field, allowing users to jump
 * multiple versions (e.g., v1 → v4 runs migrations 2, 3, and 4).
 */
export abstract class BaseMigration {
  /**
   * Migration order number
   * - Order 2: v1 → v2
   * - Order 3: v2 → v3
   * - Order 4: v3 → v4
   * etc.
   */
  abstract readonly order: number;

  /**
   * Source version this migration upgrades from
   * e.g., "1.x", "3.x"
   */
  abstract readonly fromVersion: string;

  /**
   * Target version this migration upgrades to
   * e.g., "2.0", "4.0"
   */
  abstract readonly toVersion: string;

  /**
   * Check if this migration should run on the given config
   *
   * @param config - Raw configuration object to check
   * @returns True if migration should run, false otherwise
   */
  abstract shouldRun(config: any): Promise<boolean>;

  /**
   * Perform the migration on the given config
   *
   * @param config - Raw configuration object to migrate
   * @returns Migrated configuration object
   */
  abstract migrate(config: any): Promise<any>;

  /**
   * Get human-readable name for this migration
   *
   * @returns Migration name
   */
  getName(): string {
    return `Migration ${this.fromVersion} → ${this.toVersion}`;
  }
}