node package manager
Easy collaboration. Discover, share, and reuse code in your team. Create a free org »

better-validator

better-validator

better-validator is my second generation object or request validator for node.js.

The aim of this validator is to

  • be simple to use
  • support a number of usage patterns including a fluent interface
  • support re-use of validator parts
  • support deep object and array validation
  • be able to customise the output structure
  • be able to customise failure messages
  • support i18n
  • use the well known validator library for string validation
  • be easily used with both express.js, koa.js and koa@next
  • written in and works with typescript (>= v2.0.0, see Section on Breaking Changes below)

Basic usage

Javascript

const Validator = require('better-validator');
const validator = new Validator(options);

Typescript

import Validator from 'better-validator';
const validator = Validator.create(options); // can also use new Validator(), but this has better type support due to trying to keep as much backwards compatibility as possible with v1.x

Options

  • failureFormatter function or formatter class that will be used to format each failure that is created. See below (quite a long way below, somewhat near the bottom).

Simple validation

const validator = new Validator();
 
validator(123).isNumber();
const errors = validator.run(); // => [] 
const validator = new Validator();
 
validator('not number').isNumber();
const errors = validator.run(); // => [{path: [], value: 'not number', failed: 'isNumber'}] 

Validate multiple objects at once:

const validator = new Validator();
 
const query = {};
const body = null;
 
validator(query).display('query').required();
validator(body).display('body').required();
const errors = validator.run(); // => [{path: ['body'], value: null, failed: 'required'}] 

Validate children of an object:

const validator = new Validator();
 
const query = {count: 5, hint: 32};
 
validator(query).required().isObject((obj) => {
  obj('count').required().isNumber().integer(); // pass 
  obj('hint').isString(); // fail 
});
const errors = validator.run(); // => [{path: ['hint'], value: 32, failed: 'isString'}] 

Validate children of an array:

const validator = new Validator();
 
const array = [{count: 5, hint: 32}];
 
validator(array).required().isObjectArray((child) => {
  child('count').required().isNumber().integer(); // pass 
  child('hint').isString(); // fail 
});
const errors = validator.run(); // => [{path: [0, 'hint'], value: 32, failed: 'isString'}] 
const validator = new Validator();
 
const array = [1, 2, 3.2, 'test'];
 
validator(array).required().isArray((item) => {
    item.isNumber().required().integer();
});
const errors = validator.run(); // => [{path: [2], value: 3.2, test: 'integer'}, {path: [3], value: 'test', test: 'isNumber'}] 

Re-usable validation parts:

const validator = new Validator();
 
const rule = (item) => {
  item.isNumber().integer().isPositive();
};
 
const errors = validator(123, rule); // => [] 
const validator = new Validator();
 
const query = {count: 5, hint: '32'};
 
const rule = (item) => item.isNumber().integer().isPositive();
 
validator(query).required().isObject((child) => {
  child('count').check(rule).lte(10); // pass 
  child('hint').check(rule); // fail 
});
const errors = validator.run(); // => [{path: ['hint'], value: '32', failed: 'isNumber'}] 

Using with express.js

const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
 
const check = Validator.koaMiddleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter()
});
 
const queryRule = (query) => {
  query('email').isEmail();
  query('date').isISO8601();
};
const bodyRule = (body) => {
  body('count').required().isNumber().integer();
  body('hint').isString();
  body().strict(); // make sure there aren't any expected properties in the body 
};
app.post('/', check.query(queryRule), check.body(bodyRule), function(req, res) {
  // ... 
});

Using with koa.js

const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
 
const check = Validator.koaMiddleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter()
});
 
const queryRule = (query) => {
  query('email').isEmail();
  query('date').isISO8601();
};
const bodyRule = (body) => {
  body('count').required().isNumber().integer();
  body('hint').isString();
  body().strict(); // make sure there aren't any expected properties in the body 
};
route.post('/', check.query(queryRule), check.body(bodyRule), otherFunction);

Using with koa@next (and koa-router@7) and typescript

import Validator from 'better-validator';
 
const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
 
const check = Validator.koa2Middleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter()
});
 
const queryRule = (query) => {
  query('email').isEmail();
  query('date').isISO8601();
};
const paramsRule = (params) => {
  params('id').required();
};
route.get('/:id/', check.query(queryRule), check.params(paramsRule), otherFunction);

If the body content does not pass the given validation check, the validator will return.

400 Bad Request
 
{
    "type": "ValidationError"
    "failures": [
        {
            "parameter": "children[0].prop",
            "value": "zxzx",
            "failed": "required"
        }
    ]
}

Breaking Changes Since v1.x

  • isArrayOf changed to isObjectArray
  • access to formatters changed to Validator.format.response.WrapperFormatter and similar

Installation

$ npm install -S better-validator

Included Validators

Following are the build-in validators. You may also use your own, see section below.

required

The various type validators will accept the specified type or null or undefined. To modify the check to not accept null or undefined, add the required() constraint.

validator(value).required();
validator(value).isString().required();
validator(value).required().isString();

All Types

validator(value).isEqual(7);
validator(value).notEqual('test');

Conditional checks

validator(value).if((value) => value < 7, (conditional) => {
  conditional.isEqual(4);
});

isObject

Used to validate that the value under test is an object, and to check it's properties.

validator(value).isObject((obj) => {
  obj('count').required().isNumber().integer();
  obj('hint').isString();
});

To ensure that the object has only the expected properties, the strict() constraint is added.

validator(value).isObject((obj) => {
  obj('count').required().isNumber().integer();
  obj('hint').isString();
}).strict();

isString

Makes sure the value is of type string.

validator(value).isString();
validator(value).isString().isEmail();

isString Checks

Checks from the library validator are included. Please see the link for more details. All checks that start with is are mounted into the isString() module along with their inverse not

  • isAfter(date), notAfter(date)
  • isAlpha(locale), notAlpha(locale)
  • isAlphanumeric(locale), notAlphanumeric(locale)
  • isAscii(), notAscii()
  • isBase64(), notBase64()
  • isBefore(date), notBefore(date)
  • isBoolean(), notBoolean()
  • isByteLength(options), notByteLength(options)
  • isCreditCard(), notCreditCard()
  • isCurrency(options), notCurrency(options)
  • isDataURI(), notDataURI()
  • isDate(), notDate()
  • isDecimal(), notDecimal()
  • isDivisibleBy(number), notDivisibleBy(number)
  • isEmail(options), notEmail(options)
  • isEmpty(), notEmpty()
  • isFQDN(options), notFQDN(options)
  • isFloat(options), notFloat(options)
  • isFullWidth(), notFullWidth()
  • isHalfWidth(), notHalfWidth()
  • isHexColor(), notHexColor()
  • isHexadecimal(), notHexadecimal()
  • isIP(version), notIP(version)
  • isISBN(version), notISBN(version)
  • isISSN(options), notISSN(options)
  • isISIN(), notISIN()
  • isISO8601(), notISO8601()
  • isIn(values), notIn(values)
  • isInt(options), notInt(options)
  • isJSON(), notJSON()
  • isLength(options), notLength(options)
  • isLowercase(), notLowercase()
  • isMACAddress(), notMACAddress()
  • isMD5(), notMD5()
  • isMobilePhone(locale), notMobilePhone(locale)
  • isMongoId(), notMongoId()
  • isMultibyte(), notMultibyte()
  • isNumeric(), notNumeric()
  • isSurrogatePair(), notSurrogatePair()
  • isURL(options), notURL(options)
  • isUUID(version), notUUID(version)
  • isUppercase(), notUppercase()
  • isVariableWidth(), notVariableWidth()
  • isWhitelisted(chars), notWhitelisted(chars)

Also regular expression checks can be performed with isMatch(regex), notMatch(regex), length(expected) and lengthInRange(lower, upper)

Like all other constraints, these amy be chained together:

validator(value).isAlphanumeric().isLowercase();

isBoolean

Makes sure the value is a boolean.

validator(value).isBoolean();
validator(value).isBoolean().isEqual(true);

isNumber

Makes sure the value is a number.

validator(value).isNumber();
validator(value).isNumber().integer();

isNumber Checks

  • integer()
  • isInRange(lower, upper), notInRange(lower, upper)
  • gt(threshold)
  • gte(threshold)
  • lt(threshold)
  • lte(threshold)
  • isPositive(), notPositive()
  • isNegative(), notNegative()
  • isZero(), notZero()

isObjectArray

Makes sure that the item is of type array, and validates the items. Also can specify minimum and maximum length of the array.

validator(value).isObjectArray((item) => {
  item('foo').isString();
  item('bar').isString().required();
  item().strict();
}).length(2);
validator(value).isObjectArray((item) => {
  // ... 
}).lengthInRange(4, 8); // 4 to 8 inclusive 
validator(value).isObjectArray((item) => {
  // ... 
}).lengthInRange(undefined, 8); // less than or equal to 8 
validator(value).isObjectArray((item) => {
  // ... 
}).lengthInRange(1); // one or more 

isArray

const array = [1, 2, 3.2, 'test'];
 
validator(array).required().isArray((item) => {
    item.isNumber().required().integer();
});
const errors = validator.run(); // => [{path: [2], value: 3.2, test: 'integer'}, {path: [3], value: 'test', test: 'isNumber'}] 

i18n

express.js

npm install -S i18n

Set up i18n as per normal

const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
const I18nExpressFormatter = Validator.format.message.I18nExpressFormatter;
 
const check = Validator.koaMiddleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter(),
  translationFormatter: new I18nExpressFormatter()
});
 
const queryRule = (query) => {
  query('email').isEmail();
  query('date').isISO8601();
};
const bodyRule = (body) => {
  body('count').required().isNumber().integer();
  body('hint').isString();
  body().strict(); // make sure there aren't any expected properties in the body 
};
app.post('/', check.query(queryRule), check.body(bodyRule), function(req, res) {
  // ... 
});

koa.js and koa@next

npm install -S koa-i18n koa-locale

Set up koa-i18n and koa-locale as per normal

import Validator from 'better-validator';
 
const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
const I18nExpressFormatter = Validator.format.message.I18nKoaFormatter;
 
const check = Validator.koa2Middleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter(),
  translationFormatter: new I18nKoaFormatter()
});
 
const queryRule = (query) => {
  query('email').isEmail();
  query('date').isISO8601();
};
const paramsRule = (params) => {
  params('id').required();
};
route.get('/:id/', check.query(queryRule), check.params(paramsRule), otherFunction);

Provided Formatters

Failure Formatter

A failure formatter can be provided in the options for a validator. This is responsible for a raw failure object and re-formatting it to match desired outcome. There is one failure formatter provided

Validator.format.failure.FailureFormatter

Example below of a provided failure formatter, showing its default option values.

const FailureFormatter = Validator.format.failure.FailureFormatter;
const PathFormatter = Validator.format.path.PathFormatter;
const formatterOptions = {
  pathElement: 'parameter',
  pathFormatter: new PathFormatter({
    initialSeparator: '',
    separator: '.'
  })
};
const validatorOptions = new FailureFormatter(formatterOptions);
const validator = new Validator(validatorOptions);
 
// will change the `path` in each failure to `parameter` and format it as an 
// string rather than an array 

Response Formatter

The middleware (express, koa and koa@next) also take a response formatter. This takes in the array of failures and determines how is is presented in the response.

Validator.format.response.WrapperFormatter

This wraps the failures in an object, based on the given staticTemplate.

const WrapperFormatter = Validator.format.response.WrapperFormatter;
const FailureFormatter = Validator.format.failure.FailureFormatter;
 
const wrapperOptions = {
  staticTemplate: {
    type: 'ValidationError'
  },
  wrapperElement: 'failures'
};
const check = Validator.koa2Middleware({
  responseFormatter: new WrapperFormatter(),
  failureFormatter: new FailureFormatter()
});
 
// will wrap the failures like {"type": "ValidationError", "failures": [...]} 

Custom Formatters

Custom formatters may be used in place of any of the provided ones.

A customer formatter is either a function or an object that has a format method.

function myFormatter(failure) {
  return {
    message: 'work something out here'
  };
}
class MyFormatter {
  format(failure) {
    return {
      message: 'work something out here'
    };
  }
}
const formatter = new MyFormatter();

Custom Validators

TODO

License

(The MIT License)

Copyright (c) 2013

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.