Proxy-validation

A very basic and simple validation utility that can be used as a helper when validating JS-objects. No smart built-in validators because - different business rules often requires custom/special validators.

You'll need to implement your own validate methods!

Code examples

Simple example #1:

const ProxyValidation = require('proxy-validation');

const UserValidationFields = {
  name: {
    validate(value, field, propertyName) {
      // Just validate that the value is not "falsy"
      if (!value) {
        throw new TypeError(`Cannot set ${propertyName} to: ${value}`);
      }
    }
  }
};

const user = ProxyValidation.from({}, UserValidationFields).initializeValidation();

user.validate(); // OK
user.name = ''; // Throws TypeError: Cannot set name to ''

Simple example #2 (using ES6 class):

const ProxyValidation = require('proxy-validation');
const { StringValidator } = require('proxy-validation/lib/validators');

const UserValidationFields = {
  firstName: {
    min: 3,
    max: 10,
    validate: StringValidator.validateField
  },
  email: {
    regexp: /^\w+@[a-zA-Z_]+?\.[a-zA-Z]{2,3}$/,
    min: 5,
    max: 200,
    // Custom (naive) validation method.
    validate(value, field, propertyName) {
      StringValidator.validateField(value, field, propertyName);
      if (!field.regexp.test(value)) {
        throw new TypeError(`Expected ${propertyName} to be a email address`);
      }
    }
  }
};

class User extends ProxyValidation {
  constructor() 
    super(UserValidationFields);

    return super.initializeValidation();
  }
}

const user = new User();
user.firstName = '1'; // Throws RangeError (string should be between 3 and 10 characters)
user.firstName = 1; // Throws TypeError (not a string)
user.email = 's@@@@error'; // Throws TypeError (expected email to be a email address)
user.unknown = []; // Throws Error (Unknown field)

Examples with validation options

const user1 = ProxyValidation.from({}, UserValidationFields);
user1.name = null; // OK
user1.validate(); // TypeError: Cannot set name to null

const user2 = ProxyValidation.from({}, UserValidationFields).initializeValidation();
user2.name = null; // TypeError: Cannot set name to null

const user3 = ProxyValidation.from({ name: 'foo' }, UserValidationFields);
user3.unknownField = 'bar';
user3.validate({ allowExtraProperties: true }); // OK

const user4 = ProxyValidation.from({}, UserValidationFields);
user4.unknownField = 'bar';
user4.validate({ allowExtraProperties: true, ignoreUndefinedProperties: true }); // OK

For more examples, see /test.

Requirements

Node 6+

Developing

# install dependencies
npm i
# run tests
npm test
# lint
npm run eslint
# check coverage
npm run coverage
# install, lint, test & coverage
npm run build-all