@bernierllc/retry-policy/src/types.ts

Atomic retry policy utilities with exponential backoff and jitter

/*
Copyright (c) 2025 Bernier LLC

This file is licensed to the client under a limited-use license.
The client may use and modify this code *only within the scope of the project it was delivered for*.
Redistribution or use in other products or commercial offerings is not permitted without written consent from Bernier LLC.
*/

/**
 * Configuration options for retry policies
 */
export interface RetryPolicyOptions {
  /** Maximum number of retry attempts */
  maxRetries: number;
  /** Initial delay in milliseconds */
  initialDelayMs: number;
  /** Maximum delay in milliseconds */
  maxDelayMs?: number;
  /** Exponential backoff factor */
  backoffFactor?: number;
  /** Whether to apply jitter to delays */
  jitter?: boolean;
  /** Function to determine if an error should trigger a retry */
  shouldRetry?: (error: any) => boolean;
  /** Callback function called before each retry attempt */
  onRetry?: (attempt: number, delay: number, error: any) => void;
  /** Callback function called when all retries are exhausted */
  onFailure?: (error: any) => void;
}

/**
 * Result of a retry policy evaluation
 */
export interface RetryPolicyResult {
  /** Whether the operation should be retried */
  shouldRetry: boolean;
  /** Delay in milliseconds before next retry */
  delay: number;
  /** Current attempt number */
  attempt: number;
  /** Whether this is the final attempt */
  isFinalAttempt: boolean;
}

/**
 * Jitter configuration for retry delays
 */
export interface JitterConfig {
  /** Type of jitter to apply */
  type: 'none' | 'full' | 'equal' | 'decorrelated';
  /** Jitter factor (0-1) */
  factor?: number;
}

/**
 * Backoff strategy configuration
 */
export interface BackoffConfig {
  /** Type of backoff strategy */
  type: 'exponential' | 'linear' | 'constant';
  /** Base delay in milliseconds */
  baseDelay: number;
  /** Maximum delay in milliseconds */
  maxDelay: number;
  /** Backoff factor for exponential strategies */
  factor?: number;
  /** Jitter configuration */
  jitter?: JitterConfig;
}