rut-kit

Core API reference for validating, formatting, and working with Chilean RUTs.

import { isValidRut, validateRut, formatRut, cleanRut, getRutCheckDigit, getErrorMessage } from 'rut-kit'

isValidRut

Validates if a Chilean RUT is valid.

function isValidRut(rut: string): boolean

Parameters

Name	Type	Description
rut	string	RUT to validate

Return

boolean - true if the RUT is valid, false otherwise.

Accepted Formats

• With dots and dash: 18.972.631-7
• Dash only: 18972631-7
• No formatting: 189726317

WARNING

Only accepts valid Chilean formats. Other separators (commas, asterisks) are rejected. Minimum RUT: 1.000.000.

Example

isValidRut('18.972.631-7')  // true
isValidRut('18.972.631-0')  // false
isValidRut('18,972,631-7')  // false

---

validateRut

Validates a RUT and returns detailed information about the result.

function validateRut(rut: string): RutValidationResult

Parameters

Name	Type	Description
rut	string	RUT to validate

Return

RutValidationResult - Object with the validation result:

// If valid
{ valid: true, rut: string }

// If invalid
{ valid: false, error: RutValidationError }

Error Types

Error	Description
invalidFormat	Invalid format, incorrect length, or disallowed characters
invalidCheckDigit	The check digit doesn't match

Example

validateRut('18.972.631-7')
// { valid: true, rut: '189726317' }

validateRut('18.972.631-0')
// { valid: false, error: 'invalidCheckDigit' }

validateRut('18,972,631-7')
// { valid: false, error: 'invalidFormat' }

---

formatRut

Formats a RUT to the specified format.

function formatRut(rut: string, format?: RutOutputFormat): string

Parameters

Name	Type	Description
rut	string	RUT to format
format	RutOutputFormat	Output format (optional)

Output Formats

Format	Result	Recommended Use
undefined (default)	18972631-7	Storage
'formatted'	18.972.631-7	Display to user
'clean'	189726317	Comparisons, APIs

Return

string - Formatted RUT.

Example

formatRut('189726317')              // '18972631-7'
formatRut('189726317', 'formatted') // '18.972.631-7'
formatRut('189726317', 'clean')     // '189726317'

TIP

This function is permissive: it accepts any input separator. It uses cleanRut() internally.

---

cleanRut

Extracts only digits and the letter K from a RUT, removing any other character.

function cleanRut(rut: string): string

Parameters

Name	Type	Description
rut	string	RUT to clean

Return

string - Clean RUT (only digits and uppercase K). Removes leading zeros.

Example

cleanRut('18.972.631-7')  // '189726317'
cleanRut('33.333.335-k')  // '33333335K'
cleanRut('18,972,631-7')  // '189726317'
cleanRut('18*972*631*7')  // '189726317'

TIP

Permissive function. Useful for cleaning data from Excel, PDFs, or other sources with non-standard separators.

---

getRutCheckDigit

Calculates the check digit of a RUT using the modulo 11 algorithm.

function getRutCheckDigit(rut: string): string

Parameters

Name	Type	Description
rut	string	RUT body (without check digit)

Return

string - Calculated check digit ('0'-'9' or 'K').

Example

getRutCheckDigit('18972631')  // '7'
getRutCheckDigit('33333335')  // 'K'
getRutCheckDigit('11111111')  // '1'

---

getErrorMessage

Converts an error type to a human-readable message.

function getErrorMessage(error: RutValidationError, messages?: RutErrorMessages): string

Parameters

Name	Type	Description
error	RutValidationError	Error type to convert
messages	RutErrorMessages	Custom messages (optional)

Return

string - Human-readable error message.

Default Messages

Error	Message
invalidFormat	'Invalid RUT format'
invalidCheckDigit	'Invalid check digit'

Example

const result = validateRut('18.972.631-0')

if (!result.valid) {
  getErrorMessage(result.error)
  // 'Invalid check digit'

  getErrorMessage(result.error, {
    invalidCheckDigit: 'RUT is not valid'
  })
  // 'RUT is not valid'
}