Architectural Patterns

class ReportFactory {
  static registeredReports = {};
  
  static register(type, ReportClass) {
    this.registeredReports[type] = ReportClass;
  }
  
  static create(type) {
    const ReportClass = this.registeredReports[type];
    if (!ReportClass) {
      throw new Error(`Report type '${type}' not registered`);
    }
    return new ReportClass();
  }
}

// Third-party plugin can register new report types
ReportFactory.register("pdf", PDFReport);
ReportFactory.register("excel", ExcelReport);

// Later, third-party code registers new type without modifying factory
ReportFactory.register("custom", CustomReport);

const report = ReportFactory.create("custom");