Strategy

Definition

The Strategy pattern defines a family of interchangeable algorithms behind a common interface. The context delegates behavior to a strategy object without knowing its implementation.

Diagram

classDiagram
    class LogTransport {
        <<interface>>
        +send(entry: LogEntry): void
        +flush?(): Promise~void~
    }

    class ConsoleTransport
    class OtlpTransport
    class SentryTransport

    LogTransport <|.. ConsoleTransport
    LogTransport <|.. OtlpTransport
    LogTransport <|.. SentryTransport

    class NotificationTransport {
        <<interface>>
        +connect(): Promise~void~
        +disconnect(): Promise~void~
        +onNotification(cb): unsubscribe
    }

    class SignalRTransport
    class SseTransport

    NotificationTransport <|.. SignalRTransport
    NotificationTransport <|.. SseTransport

Implementation in Granit

Strategy interface	Package	Implementations
LogTransport	@granit/logger	createConsoleTransport(), createOtlpTransport()
NotificationTransport	@granit/notifications	createSignalRTransport(), createSseTransport()
CookieConsentProvider	@granit/cookies	createKlaroCookieConsentProvider()

Rationale

Log destinations and real-time notification channels vary by deployment. The Strategy pattern lets applications compose the exact set of transports they need without modifying framework code. A Sentry transport can be added alongside the console transport without either knowing about the other.

Usage example

import { createLogger, createConsoleTransport } from '@granit/logger';
import type { LogTransport, LogEntry } from '@granit/logger';

// Custom Sentry transport
const sentryTransport: LogTransport = {
  send(entry: LogEntry) {
    if (entry.level === 'ERROR') {
      Sentry.captureMessage(entry.message, {
        level: 'error',
        extra: entry.context,
      });
    }
  },
};

// Combine console + Sentry
const logger = createLogger('app', {
  transports: [createConsoleTransport(), sentryTransport],
});

logger.error('Critical failure', new Error('timeout'));
// → Both console and Sentry receive the entry

Transports with a flush() method are automatically flushed on beforeunload.

Further reading

• Strategy — refactoring.guru