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Function: toResultWith()

Call Signature​

toResultWith<T, E, F>(validation, combineErrors): Result<T, F>

Defined in: validation/toResult/index.ts:118

Converts a Validation to a Result, combining all errors into a single error.

Like toResult, but uses a function to combine multiple errors into a single error. This is useful when you need a Result with a single error value instead of an array.

Type Parameters​

T​

T

E​

E

F​

F

Parameters​

validation​

Validation<T, E>

The Validation to convert

combineErrors​

(errors) => F

Function to combine errors array into single error

Returns​

Result<T, F>

A Result with the value or combined error

Example​

// Combine errors into a message
toResultWith(
  invalid(['Error 1', 'Error 2', 'Error 3']),
  (errors) => errors.join('; ')
)
// => Err('Error 1; Error 2; Error 3')

// Use first error only
toResultWith(
  invalid(['Error 1', 'Error 2']),
  (errors) => errors[0] ?? 'Unknown error'
)
// => Err('Error 1')

// Real-world: Create structured error
const toApiResult = (validation: Validation<User, string>) =>
  toResultWith(validation, (errors) => ({
    status: 400,
    code: 'VALIDATION_ERROR',
    message: 'Validation failed',
    details: errors
  }))

// Real-world: Format for display
const toDisplayResult = (validation: Validation<Data, FieldError>) =>
  toResultWith(validation, (errors) => ({
    title: 'Please fix the following errors:',
    items: errors.map(e => `${e.field}: ${e.errors.join(', ')}`)
  }))

See​

  • toResult - for keeping errors as array
  • fromResult - for converting Result to Validation

Call Signature​

toResultWith<E, F>(combineErrors): <T>(validation) => Result<T, F>

Defined in: validation/toResult/index.ts:122

Converts a Validation to a Result, combining all errors into a single error.

Like toResult, but uses a function to combine multiple errors into a single error. This is useful when you need a Result with a single error value instead of an array.

Type Parameters​

E​

E

F​

F

Parameters​

combineErrors​

(errors) => F

Function to combine errors array into single error

Returns​

A Result with the value or combined error

<T>(validation): Result<T, F>

Type Parameters​

T​

T

Parameters​

validation​

Validation<T, E>

Returns​

Result<T, F>

Example​

// Combine errors into a message
toResultWith(
  invalid(['Error 1', 'Error 2', 'Error 3']),
  (errors) => errors.join('; ')
)
// => Err('Error 1; Error 2; Error 3')

// Use first error only
toResultWith(
  invalid(['Error 1', 'Error 2']),
  (errors) => errors[0] ?? 'Unknown error'
)
// => Err('Error 1')

// Real-world: Create structured error
const toApiResult = (validation: Validation<User, string>) =>
  toResultWith(validation, (errors) => ({
    status: 400,
    code: 'VALIDATION_ERROR',
    message: 'Validation failed',
    details: errors
  }))

// Real-world: Format for display
const toDisplayResult = (validation: Validation<Data, FieldError>) =>
  toResultWith(validation, (errors) => ({
    title: 'Please fix the following errors:',
    items: errors.map(e => `${e.field}: ${e.errors.join(', ')}`)
  }))

See​

  • toResult - for keeping errors as array
  • fromResult - for converting Result to Validation