index.js

import {Validator} from 'Validator'

// Usage
console.log(Validator('valid@email.com', {type: "email", placeholder: "your email"}))
// []

console.log(Validator('invalid.email.com, but no type="email"', {placeholder: "your email"}))
// []

console.log(Validator('invalid.email.com', {type: "email", placeholder: "your email"}))
// [{error: "Not valid email address"}]

console.log(Validator('Check max length', {maxLength: "6"}))
// [{error: "More than %s symbols", length: 6}]

Validator.js

export const Validator = (value, props, ...customValidators) => (validators => validators.reduce((errors, validate) => [...errors, ...validate(value, props)], []))([
    // Here the list of validators
    (value, props) => typeof value !== 'string'
        || props.type !== 'email'
        || /^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(value.toLowerCase()) ? [] : [{error: Errors.EMAIL}],
    (value, props) => typeof value !== 'string'
        || typeof props.maxLength === 'undefined'
        || parseInt(props.maxLength) >= value.length ? [] : [{error: Errors.MAXLENGTH, length: parseInt(props.maxLength)}],
    /**
     * Other validators here
     * We can extend wherever we want following the interface
     * const newAwesomeValidator = (value, props, ...customValidators) => Validator(
     *     value,
     *     props,
     *     (value, props) => [],
     *     (value, props) => [],
     *     (value, props) => [],
     *     ...customValidators
     * )
     */
    ...customValidators
])

export const Errors = {
    EMAIL: "Not valid email address",
    MAXLENGTH: "More than %s symbols"
}

export default {Validator, Errors}