Error Handling Types

Since 1.9.0

Types for advanced error handling patterns.

Overview

Error Handling Types provides type-level error handling utilities. It supports Result types, Either types, Option types, error chains, recovery strategies, and domain-specific errors.

This module enables building type-safe error handling applications with proper constraints for error types, recovery mechanisms, and validation errors.

Basic Usage

import type { Result, Either, Option, ValidationError, RecoveryStrategy } from 'uni-types'

// Define result type
type ApiResult = Result<Data, NetworkError>

// Define either type
type ConfigValue = Either<ValidationError, Config>

// Define option type
type MaybeValue = Option<string>

Key Types

Result

Result type (Success or Failure).

type Result<T, E = Error> = Success<T> | Failure<E>

Success

Success result.

interface Success<T> {
  ok: true
  value: T
}

Failure

Failure result.

interface Failure<E> {
  ok: false
  error: E
}

Either

Either type (Left or Right).

type Either<L, R> = Left<L> | Right<R>

Left / Right

Left and Right values.

interface Left<L> {
  type: 'left'
  value: L
}

interface Right<R> {
  type: 'right'
  value: R
}

Option

Option type (Some or None).

type Option<T> = Some<T> | None

Some / None

Some and None values.

interface Some<T> {
  type: 'some'
  value: T
}

interface None {
  type: 'none'
}

ErrorBase

Base error structure.

interface ErrorBase<T extends ErrorType = ErrorType> {
  type: T
  message: ErrorMessage
  code?: ErrorCode
  stack?: ErrorStack
  cause?: unknown
  timestamp?: number
  context?: Record<string, unknown>
}

CustomError

Custom error type.

interface CustomError<T = unknown> extends ErrorBase<string> {
  name: string
  data?: T
  retryable?: boolean
  severity?: ErrorSeverity
}

ErrorSeverity

Error severity levels.

type ErrorSeverity = 'low' | 'medium' | 'high' | 'critical'

RecoveryStrategy

Recovery strategy types.

type RecoveryStrategy =
  | 'retry' // Retry the operation
  | 'fallback' // Use fallback value
  | 'default' // Use default value
  | 'skip' // Skip and continue
  | 'abort' // Abort operation
  | 'escalate' // Escalate to higher handler

RetryConfig

Retry configuration.

interface RetryConfig {
  maxAttempts: number
  delay: number
  backoff?: 'linear' | 'exponential' | 'fixed'
  maxDelay?: number
  retryOn?: (error: Error) => boolean
  onRetry?: (error: Error, attempt: number) => void
}

ValidationError

Validation error type.

interface ValidationError<T = unknown> extends CustomError<'validation'> {
  type: 'validation'
  field?: string
  path?: string
  value?: T
  constraint?: string
}

NetworkError

Network error type.

interface NetworkError extends CustomError<'network'> {
  type: 'network'
  status?: number
  statusText?: string
  url?: string
  retryable?: boolean
  timeout?: boolean
}

AuthenticationError

Authentication error type.

interface AuthenticationError extends CustomError<'authentication'> {
  type: 'authentication'
  code?: 'unauthorized' | 'forbidden' | 'token_expired' | 'invalid_token'
}

TimeoutError

Timeout error type.

interface TimeoutError extends CustomError<'timeout'> {
  type: 'timeout'
  operation?: string
  timeoutMs?: number
}

Panic

Panic type (unrecoverable error).

interface Panic extends CustomError<'panic'> {
  type: 'panic'
  fatal: true
  exitCode?: number
}

Related

• Event System - Event handling types
• Functional Programming - Functional patterns
• Validation - Validation types