Error

The CerebralError class allows you to create custom error types that integrate with Cerebral’s error handling system. Custom errors can be caught specifically in the module’s catch configuration.

Creating Custom Errors∞ 

Extend the CerebralError class to create custom error types:

import { CerebralError } from 'cerebral'

export class AuthenticationError extends CerebralError {
  constructor(message, details) {
    super(message, details)
    this.name = 'AuthenticationError' // Override the default name
  }
}

// With additional properties
export class ApiError extends CerebralError {
  constructor(message, statusCode, responseData) {
    super(message, { responseData }) // Details passed to parent
    this.name = 'ApiError'
    this.statusCode = statusCode // Custom property
  }
}

Error Properties∞ 

The CerebralError includes these properties:

• name: Error type name, defaults to ‘CerebralError’ (should be overridden)
• message: The error message
• details: Optional object with additional error details
• stack: Stack trace (automatically generated)

Throwing Errors∞ 

Throw custom errors in actions or providers:

import { AuthenticationError } from './errors'

function authenticate({ props }) {
  if (!props.token) {
    throw new AuthenticationError('Invalid token', {
      attempted: true,
      userId: props.userId
    })
  }

  // Continue with authentication
}

Catching Errors∞ 

Errors are caught in the module’s catch configuration:

import { AuthenticationError, ApiError } from './errors'
import * as sequences from './sequences'

export default {
  // ...module definition
  catch: [
    // Catch specific error types
    [AuthenticationError, sequences.handleAuthError],
    [ApiError, sequences.handleApiError],

    // Generic fallback (catches any Error)
    [Error, sequences.handleGenericError]
  ]
}

Error Handling Propagation∞ 

Serialization∞ 

CerebralError instances can be serialized to JSON, which includes all properties except ‘toJSON’, ‘execution’, and ‘functionDetails’:

try {
  throw new ApiError('Failed to fetch data', 404, { error: 'Not found' })
} catch (error) {
  console.log(JSON.stringify(error))
  // Output includes: name, message, details, statusCode, stack
}