Built-in Rules

@pliant/core includes 11 production-ready rules that cover common validation scenarios. All rules are tree-shakeable—only the rules you import are included in your bundle.

Rule List

Rule	Description	Common Use
required	Value must be present	Required fields
email	Valid email format	Email inputs
numeric	Numeric characters only	ID numbers
length	Length within range	Usernames, passwords
minLength	Minimum length	Passwords
maxLength	Maximum length	Comments, bios
range	Number within range	Age, quantity
min	Minimum value	Prices
max	Maximum value	Limits
regex	Pattern matching	Phone, postal code
equals	Value equality	Password confirm

Quick Reference

import {
  requiredRule,    // required()
  emailRule,       // email({ allowEmpty? })
  numericRule,     // numeric()
  lengthRule,      // length({ min?, max? })
  minLengthRule,   // minLength({ min })
  maxLengthRule,   // maxLength({ max })
  rangeRule,       // range({ min, max })
  minRule,         // min({ min })
  maxRule,         // max({ max })
  regexRule,       // regex({ pattern, invert? })
  equalsRule       // equals({ field?, value? })
} from '@pliant/core';

Usage Pattern

All rules follow the same pattern:

import { createRegistry, addRules, ruleNameRule } from '@pliant/core';

const registry = createRegistry();

addRules(registry, {
  ruleName: ruleNameRule(options)
});

Complete Example

import {
  createRegistry,
  addRules,
  evaluateRules,
  requiredRule,
  emailRule,
  lengthRule,
  minLengthRule,
  rangeRule,
  regexRule,
  equalsRule
} from '@pliant/core';

const registry = createRegistry();

addRules(registry, {
  required: requiredRule(),
  email: emailRule(),
  username: lengthRule({ min: 3, max: 20 }),
  password: minLengthRule({ min: 8 }),
  age: rangeRule({ min: 18, max: 120 }),
  phone: regexRule({ pattern: /^\d{10}$/ }),
  confirmPassword: equalsRule({ field: 'password' })
});

Inheritance

All rules can be extended with inheritRule():

import { inheritRule, minLengthRule } from '@pliant/core';

const strongPassword = inheritRule(minLengthRule({ min: 12 }), {
  code: 'strongPassword'
});

See Rule Inheritance for details.

Custom Rules

Need something specific? See Custom Rules.

Async Rules

For server-side validation, see Async Rules.