String validators

minLength

Validates that a text field meets a minimum character length.

Property	Type	Required	Description
`value`	`number`	Yes	Minimum required character length (inclusive)

{
  type: 'minLength',
  value: 8,
  message: 'Password must be at least 8 characters'
}

maxLength

Validates that a text field does not exceed a maximum character length.

Property	Type	Required	Description
`value`	`number`	Yes	Maximum allowed character length (inclusive)

{
  type: 'maxLength',
  value: 255,
  message: 'Description cannot exceed 255 characters'
}

regex

Validates that a field matches a specified regular expression pattern.

Property	Type	Required	Description
`pattern`	`string \| RegExp`	Yes	Regular expression pattern to match

{
  type: 'regex',
  pattern: '^[A-Z]{3}-\\d{4}$',
  message: 'Must match format: ABC-1234'
}

email

Validates that a field contains a properly formatted email address according to RFC standards.

{
  type: 'email',
  message: 'Please enter a valid email address',
  options: {
    allow_display_name: false,
    require_tld: true,
    allow_underscores: false
  }
}

Options:

All options are optional. The validator uses sensible defaults when options are not specified.

Option	Type	Default	Description
`allow_display_name`	`boolean`	`false`	Allow "Display Name <email@example.com>" format
`require_display_name`	`boolean`	`false`	Require display name format
`allow_utf8_local_part`	`boolean`	`true`	Allow non-English UTF8 characters in local part
`require_tld`	`boolean`	`true`	Require top-level domain (e.g., .com, .org)
`ignore_max_length`	`boolean`	`false`	Skip standard email length validation
`allow_ip_domain`	`boolean`	`false`	Allow IP addresses as domain (e.g., user@192.168.1.1)
`domain_specific_validation`	`boolean`	`false`	Enable provider-specific validation (e.g., Gmail rules)
`allow_underscores`	`boolean`	`false`	Allow underscores in local part
`host_whitelist`	`string[]`	-	Only allow emails from these domains
`host_blacklist`	`string[]`	-	Reject emails from these domains
`blacklisted_chars`	`string`	-	Reject emails containing these characters

Examples:

Corporate emails only:

{
  type: 'email',
  options: {
    host_whitelist: ['company.com', 'company.net'],
    require_tld: true
  }
}

Allow internal emails:

{
  type: 'email',
  options: {
    require_tld: false,  // Allow user@localhost
    allow_ip_domain: true
  }
}

Strict validation:

{
  type: 'email',
  options: {
    domain_specific_validation: true,
    allow_underscores: false,
    blacklisted_chars: '!#$%'
  }
}

url

Validates that a field contains a properly formatted URL including protocol, domain, and optional path.

Property	Type	Required	Default	Description
`options.protocols`	`string[]`	No	`['http', 'https']`	Allowed URL protocols
`options.require_protocol`	`boolean`	No	`false`	Whether protocol is required
`options.require_host`	`boolean`	No	`true`	Whether host is required
`options.require_valid_protocol`	`boolean`	No	`true`	Whether protocol must be valid
`options.allow_underscores`	`boolean`	No	`false`	Allow underscores in hostname
`options.allow_trailing_dot`	`boolean`	No	`false`	Allow trailing dot in hostname
`options.allow_protocol_relative_urls`	`boolean`	No	`false`	Allow URLs starting with //
`options.allow_query_components`	`boolean`	No	`true`	Allow query parameters

{
  type: 'url',
  options: {
    protocols: ['https'],
    require_protocol: true
  }
}

String validators

minLength

maxLength

regex

email

url

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