v-rule

Light and flexible validation rules for form

Advantages:

• Limited API, save you from complicated configuration
• Quite flexible, able to compose any validation rule
• Small library with no dependence

Core API

• when(key: string, assert?: func)
• whenNot(key: string, assert?: func)
• expect(desc: string, assert?: func)
• validate(key: string)

Install

npm i -S v-rule

Example - Order beer in restaurant

1

import v from 'v-rule'

const validation = v.create({
    // alternative v.expect('This is required')
    seat: v.expect('This is required', c => c['seat'] !== '')
})
const result = validation.test({ seat: '' })
// => { pass: false, messages: { seat: 'This is required' } }

2

import v from 'v-rule'

const validation = v.create({
    seat: v.expect('This is required', c => c['seat'] !== ''),
    age: v.when('drink', c => c['drink'] === 'budweiser')
    .expect('Required when drink beer')
})
const result = validation.test({ seat: '6', drink: 'budweiser', age: '' })
// => { pass: false, messages: { age: 'Required when drink beer' } }

3

import v from 'v-rule'

const validation = v.create({
    seat: v.expect('This is required', c => c['seat'] !== ''),
    age: v.when('drink', c => c['drink'] === 'budweiser')
    .expect('Required when drink beer')
    .expect('You should be older than 18', c => c['age'] > 17)
})
const result = validation.test({ seat: '6', drink: 'budweiser', age: 16 })
// => { pass: false, messages: { age: 'You should be older than 18' } }

4

import v from 'v-rule'

const validation = v.create({
    seat: v.expect('This is required', c => c['seat'] !== ''),
    age: v.when('drink', c => c['drink'] === 'budweiser')
    .expect('Required when drink beer')
    .expect('You should be older than 18', c => c['age'] > 17)
})
const result = validation.test({ seat: '6', drink: 'budweiser', age: 18 })
// => { pass: true, messages: {} }

Usage

Preset

import { preset } from 'v-rule'

const v = preset({
    required: (expect) => expect(`required`),
    min: (expect, n) => expect(`> ${n}`, c => c['$0'] > n),
    max: (expect, m) => expect(`> ${m}`, c => c['$0'] < m),
})
const validation = v.create({
    number: v.required().min(4).max(30)
})

Multi rules

const validation = v.create({
    age: [
        v.expect('required')
        .expect('should be number', c => v.isInteger(c.age)), // 1st rule
        v.when('min') // 2nd rule, only execute when 1st rule pass
        .when('max')
        .expect(
            'should between min and max',
            c => c.min < c.age && c.age < c.max
        )
    ]
})

const result = validation.test({ age: '17', min: 18, max: 50 })
// => r { pass: false, messages: { age: 'should between min and max' } }

Trigger another rule

const validation = v.create({
    beer: v.when('beer').validate('age'), // or v.validate('age')
    age: v.expect('age should be greater than 18', c => c.age > 18)
})

const context = {age: '17'}
const result = validation.test({ beer: 1 }, context)
// => { pass: false, messages: { age: 'age should be greater than 18' } }

Test all rules

v.test only tests with available values in obj whereas testAllRules will default unavailable value to {key: undefined} and test against all rules. Use v.testAllRules when submit form.

const validation = v.create({
    name: v.expect('required'),
    pwd: v.expect('required')
})
let r = validation.testAllRules({ name: 'a' })
// => { pass: false, messages: { name: '', pwd: 'required' } }