pretty-validate

A lightweight and minimalistic library designed for serverside validations. This library uses some of the validation rules from validator.js with some key differences:

The following validation rules do not assert to receive a string value before the validation:

Rules	Description
isBoolean	only raw boolean values: true and false values are considered valid. Thus, "true" or 0 will not be considered as a valid value;
isInt	only integer value types are considered valid (validated with Number.isInteger(value) method).
isNumber	only numeric values are considered valid. For instance, 3.14 is valid value, while '3.14',false, 'a', {} are all invalid.

Other useful rules:

Rules	Description
isString	Checks whether a passed value is an instance of string type.
isEnum	Specify valid enum values for a parameter.
required	Checks whether a required value is not null, undefined or ''.
toUpperCase	Converts the passed string to upper cased.
toLowerCase	Converts the passed string to lower cased.

Installation and Usage

Install the library with npm install pretty-validate

Usage

Validator Class comes with the validate methods and the list of the validation rules and sanitizers. For the full list of the rules, please see the validator.js library documentation.

validate() options

• strict: optional boolean; if true, extra properties in validated object will result in error.
• discardExtraProps: options boolean; if true, extra properties will be deleted from the validated object.

import Validator from 'pretty-validate';

const validator = new Validator();

try {
  validator.validate(
    ctx.request.body,
    {
      email: {
        required: true,
        isEmail: true,
        errorMessage: 'Your custom error message if field fails the validaton'
      },
      password: {
        required: true,
        isStrongPassword: true,
      },
      firstName: {
        isString: true,
      },
      lastName: {
        isString: true,
        toUpperCase: true,
      },
      age: {
        required: true,
        isInt: { min: 0, max: 99 },
      },
    },
    {
      strict: true,
    },
  );
} catch (error) {
  // handle error here
}

Koa Example:

An easiest and elegant way to use this library is to define your own wrapper. In this wrapper you can define custom validation rules and handle validation errors.

Wrapper example - my-validation.js:

import Validator from 'pretty-validate';

const customSanitizers = {
  toFooBared: (value) => {
    return `${value}+fooBar`;
  },
};

const customValidators = {
  isFooBared: (value) => {
    return value.includes('fooBar');
  },
};

const validator = new Validator({
  customSanitizers,
  customValidators,
});

export function validate(target, validations, options) {
  try {
    validator.validate(target, validations, options);
  } catch (error) {
    const { message, details } = error;

    // Handle your error here.
    // You can throw another error here to let your error handling middleware handle this
  }

  return true;
}

In your Routes, you would use your wrapper function.

import * as Router from '@koa/router';
import { validate } from './my-validation';

export const router = new Router({});

router.post('/signin', async (ctx) => {
  validate(ctx.request.body, {
    username: { required: true, isString: true },
    password: { required: true, isString: true },
  });
  // Validation is done. If something is not right, validate method will throw an error.
  // Your error handling middleware should handle the error and return 400 error with an error message.
});

License (MIT)

Copyright (c) 2021 Kamran Naghiyev

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.