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1.1.0 • Public • Published


Data validator which allows:

  • defining customizable validators (global and local)
  • defining aliases (global and local)
  • validate data in bulk operation
  • canonization of data
  • retrieve list of errors
  • retrieve list of valid values
  • allow optional data and default values
  • perform strict/non-strict validation



Install with npm

npm install bulk-validator

Basic Usage

var Validator = require('bulk-validator').Validator;
var weekDays = { MON: 0, TUE: 1, WED: 2, THU: 3, FRI: 4, SAT: 5, SUN: 6 };
// perform data validation of some common data in a bulk operation
var validator = new Validator();
validator.str('name', 'Daniel Berlanga')
         .num('luckyNumber', '7')
         .str('birthday', '1801-04-09', { regExp: /\d{4}-\d{2}-\d{2}/ })
         .bool('male', 1).
         .enumeratedKeyValue('day', 'FRI', { enumerated: weekDays });
// check for errors
if(validator.errors()) {
  return {
    status: 'error',
    errors: validator.errors(),
// get the valid data
var validData = validator.valid();
 // note how luckyNumber and male have been converted to Number and Boolean
 // day also has been returned as its enumerated value instead of the key
   "name": "Daniel Berlanga",
   "luckyNumber": 7,
   "birthday": "1801-04-09",
   "male": true,
   "day": 4

Validator global options

This is the list of global options of the validators.

They can be accessed and modified through the static object in Validator.defaultOptions, which will be applied to all the new instances created.

Instances created before modifying this object won't be affected.

Validator.defaultOptions.optional = false;
var v1 = new Validator();
Validator.defaultOptions.optional = true;
var v2 = new Validator();
// v1 still has optional set to false
// v2 has optional set to true by default

This options can be overridden in each validation like this:

var v = new Validator({
  defaultValue: -1,
  returnNullOnErrors: false
v.num('n1', 0)
 .num('n2', undefined)
 .num('n3', undefined, { optional: true })
 .num('n4', undefined, { optional: true, defaultValue: 100 });
v.valid();  // { n1: 0, n3: -1, n4: 100 }
v.errors(); // { n2: undefined }


If set to true, default validators will usually apply strict comparison/validation (i.e. using === instead of ==, or doing type checking).

It's also one of the options passed to the custom validators, and can/need be used when implementing them.

Default value: false


When true, if the data is valid, it's value will be converted to the one returned by the validator. If false, the data will be validated but the original will be preserved (i.e. v.num('n', '123') will return 123 or '123' depending on this option)

Default value: true


If this option is true and any of the passed data fails the validation, calling valid() will return null. Set to false if you still want to retrieve the valid values.

Default value: true


If you don't care about providing (a lot of) information of the failed validation, you can set this option to true and no other validation will be performed once there's an error.

This should give you a few more free CPU cycles ;)

Default value: false


Mark the data as optional (all of them is specified in Validator.defaultOptions, the options passed to the Validator constructor, or only a parameter if passed to a validation method.

If true, a validation won't fail if the data value is undefined and the data will be asigned with defaultValue if specified.

It will still fail for other values like null, 0, false, etc.

Default value: false


If options.optional is set to true and the data is undefined, it will be assigned with the value defined here.


= new Validator();
v.str('data', undefined, {
  optional: true,
  defaultValue: 'hello world'
// v.valid().data === 'hello world'

Default value: undefined


If a value is validated with undefined, and this option is false, it won't be included in the list of valid values.

This is useful when we want define a schema with optional values, and we set options.optional to true.

Default value: true


List of validators to add locally to a new Validator when instanciated. It should be defined as set like { name: definition }


var v = new Validator({ validators: {
  allPass: function(data, options) {
    return {
      data: data,
      valid: true
v.allPass('foo', 'bar');
v.allPassArray('foo', ['bar']);
v.allPassObject('foo', { k: 'bar' });

Default value: undefined


This option protects the already created validators.

Set it to true if you wanna get rid of any of them or override its behavior with a custom one.

Note: Trying to override any method with this option set to false will throw an Error.

Default value: false


This option allows to return the data (in valid() or errors() depending on externalShouldFail option) instead of ignoring the data without a definition when validating objects in an schema.


var v = new Validator();
v.addSchema('test', {
  foo: { validator: 'num' },
  bar: { validator: 'str' },
var data = {
  foo: 123,
  bar: 'xyz',
  other: 'external'
v.schema('test', data);
// v.valid() === { foo: 123, bar: 'xyz' }
// v.error() === null
v.schema('test', data, { includeExternal: true });
// v.valid() === { foo: 123, bar: 'xyz' }
// v.error() === { other: 'external' }
v.schema('test', data, { includeExternal: true, externalShouldFail: false });
// v.valid() === { foo: 123, bar: 'xyz', other: 'external' }
// v.error() === null

Default value: false


This option is only used when includeExternal is true (otherwise external values are just ignored).

By default, external values will fail the validation as they are not defined in the schema, but setting this option to false will return them in the valid() result:

var v = new Validator();
v.addSchema('test', {
  foo: { validator: 'num' },
  bar: { validator: 'str' },
var data = {
  foo: 123,
  bar: 'xyz',
  other: 'external'
v.schema('test', data, { includeExternal: true, externalShouldFail: true });
// v.valid() === { foo: 123, bar: 'xyz' }
// v.error() === { other: 'external' }
v.schema('test', data, { includeExternal: true, externalShouldFail: false });
// v.valid() === { foo: 123, bar: 'xyz', other: 'external' }
// v.error() === null

Default value: true


Setting this option to a function, you can set it to be called everytime a validation is going to be done, before it happens. The input data is the raw value to be validated, and the result is the actual value that is going to be passed to the validator.


// get the data and return it times 10
function times10(data) {
  return data * 10;
// validate only numbers greater or equal than 50
var v = new Validator();
// 10 without transform is 10
v.num('raw', 10, { min: 50 });
// 10 transformed, is 100
v.num('transformed', 10, { min: 50, preTransform: times10 });
// v.valid().transformed === 100
// v.errors().raw === 10

Applying it to the raw data means that if the data to validate is an array or an object, it's applied to the whole data itself, not to each of its elements.

function addElement(data) {
  if (isArray(data)) {
    return data.concat([0]);
  } else if (isObject(data)) {
    return {
      extra: 0,,
  } else {
    return data;
var v = new Validator({ preTransform: addElement });
v.num('single', 123);
v.numArray('list', [10, 20, 30]);
v.numObject('object', { a: 10, b: 20, c: 30 });
// v.valid() === {
//  single: 123,
//  list: [10, 20, 30, 0],
//  object: { a: 10, b: 20, c: 30, extra: 0 },
// }

If the transformation data triggers any error, the data won't validate.

Default value: undefined


Works like preTransform but the callback is applied to each element before the validation (but after preTransform is applied):

// validate only numbers greater or equal than 50
var v = new Validator({ min: 50 });
v.num('single', 10);
v.num('list', [10, 20, 30]);
v.num('object', { a: 10, b: 20, c: 30 });
v.num('transformedSingle', 10, { preTransformItem: times10 });
v.num('transformedList', [10, 20, 30], { preTransformItem: times10 });
v.num('transformedObject', { a: 10, b: 20, c: 30 }, { preTransformItem: times10 });
// v.valid() === {
//  transformedSingle: 100,
//  transformedList: [100, 200, 300],
//  transformedObject: { a: 100, b: 200, c: 300 },
// }
// v.errors() === {
//  single: 10,
//  list: [10, 20, 30],
//  object: { a: 10, b: 20, c: 30 },
// }


Works like preTransformItem but the callback is applied to each item, after the validation.


Works like preTransform but the callback is applied just before the data is returned (and after all preTransformItem are applied).

Notes about transformation functions

When applying transformations, the process is like described here:

  1. Apply preTransform functions (if defined) to the raw data
  2. Apply preTransformItem functions (if defined) to each raw item
  3. Apply the validation to the data (each item for ~Array and ~Object variants)
  4. Apply postTransformItem functions (if defined) to each validated item (if canonized option is true, canonization will be done before this step)
  5. Apply postTransform functions (if defined) to the final result before being stored in the valid item list
  • For single validations, preTransform and preTransformItem are applied both, in that order.
  • For single validations, postTransformItem and postTransform are applied both, in that order.
  • If a transformation function fails (i.e. triggering an error), the validation fails (the data will be in errors()) without triggering any error

List of default validators


The data will pass the validation if is not undefined.


The validation process will depend on the strict option.

If the strict is set to true, it will pass the validation only if it's type is strictly a Boolean.

If the strict is set to false, it will pass the validation always. Also, its value will be set to the casting of the data (i.e. 0 will be false, 1 true). In case of strings, it will evaluate to true if it's not '', 'false' or '0'.


The validation process will depend on the strict option.

When strict is set to true, it will only validate if it's a number (isNumber). If strict is false, it will accept also numeric values (isNumeric) and Infinity.

It accepts also other validation options:

  • rangeMin and rangeMax: If any of this options is set, it will only accept values greater/less than the specified (as rangeMin < data < rangeMax).
  • minEq and maxEq: By default this options are false, but if set to true, if set rangeMin or rangeMax will perform the comparisons with the <=/>= operators instead of </>.
  • regExp: If this option is set (to a string or a valid RegExp), the data need to match it to pass thte validation.

There are also some options that don't accept the validation, but modificate the canonized value (when canonize is true):

  • integer: when set to true the data will be converted to integer (before applying any other condition)
  • min and max: it will clamp the data to avoid outer values


// Accept only numbers greater or equal than 10 and less than 20, which ends in ".0" or ".5"
var v = new Validator({
  rangeMin: 10,
  rangeMax: 20,
  minEq: true,
  regExp: '\.[35]$'
v.num('n1', 5.5)   // fail: it's less than 10
 .num('n2', 10)   // fail: don't match the regular expression
 .num('n3', 10.0)   // fail: a number like this is passed as 10, not as 10.0
 .num('n4', '10.0') // pass: it's a string but strict is set to false by default (and preserves the decimal part)
 .num('n5', 11.3)   // fail: it doesn't match the regular expressoin
 .num('n6', 15.5)   // pass
 .num('n7', 20.0); // fail: it's equal to rangeMax, but it's compared with < and not with <=
// accept all numeric values, setting them to 0 if negatives, and removing their decimal part
var v = new Validator({
  integer: true,
  min: 0
v.num('n1', -3)                         // it will pass, and its value will be set to 0
 .num('n2', 1000)                       // pass, there's no upper limit
 .num('n3', 10.5)                       // pass and it's value will be set to 10 (integer)
 .num('n4', -5.9, { min: -Infinity }); // pass and it's value will be set to -5


Accepts strings.

Like num, its validation process depends on the strict option: When true it will only accept data of the string type. If false, it will accept all kind of data that can be converted to string.

It accept also the following options:

  • minLength: If specified, the data won't validate unless its length is greater or equal than this option.
  • maxLength: If specified, the data won't validate unless its length is less than this option.
  • truncate: If true the string will pass the validation, but will be truncated.
  • append: If specified AND the string is truncated, this string will be appended. Nothing is appended if the string length is less than maxLength (see truncate).
  • regExp: If specified, it needs to match the RegExp to validate. It's applied after truncate, but before lowerCase and upperCase.
  • lowerCase: If true, the string will be transformed to lower case.
  • upperCase: If true, the string will be transformed to upper case.


var v = new Validator({ returnNullOnErrors: false });
v.str('s0', '', { minLength: 3 })
 .str('s1', 'test string', { minLength: 3 })
 .str('s2', 'abcdefghijklmmnopqrstuvwxyz', { maxLength: 10 })
 .str('s3', 'abcdefghijklmmnopqrstuvwxyz', { maxLength: 10, truncate: true })
 .str('s4', 'abcdefghijklmmnopqrstuvwxyz', { maxLength: 10, truncate: true, append: '...' })
 .str('s5', 'AbCdE', { lowerCase: true });
v.valid();   // {
             //   s1: "test string"
             //   s3: "abcdefghij"
             //   s4: "abcdefghij..."
             //   s5: "abcde"
             // }
v.errors();  // {
             //   s0: '',
             //   s2: "abcdefghijklmmnopqrstuvwxyz"
             // }


This is a very simple validator that will pass the data only if they are functions. In this validator, the option strict has no effect.

var v = new Validator();
v.fn('f1', function() {})    // pass, valid function
 .fn('f2', 'function() {}'); // fail (it's a string, not a function)


This validator checks that the passed data is one of the values defined in an object. The strict option defines if the comparison should be done strictly (===) or not (==).

You need to pass the object where the definitions are in the enumerated option.

var weekDays = { MON: 0, TUE: 1, WED: 2, THU: 3, FRI: 4, SAT: 5, SUN: 6 };
var v = new Validator({ enumerated: weekDays, returnNullOnErrors: false });
v.enumerated('e1', 0)
 .enumerated('e2', 4)
 .enumerated('e3', weekDays.THU)
 .enumerated('e4', 'SUN')         // fail: SUN is not a value of the enumerated (is a key)
 .enumerated('e5', 'Friday')      // fail: Ok this has nothing to do here...
 .enumerated('e6', 10);           // fail: This value is not in the enumerated object
v.valid(); // { e1: 0, e2: 4, e3: 3 }


This validator works like enumerated, but checks if the value is one of the keys of the object.

You need to pass the object where the definitions are in the enumerated option.

var weekDays = { MON: 0, TUE: 1, WED: 2, THU: 3, FRI: 4, SAT: 5, SUN: 6 };
var v = new Validator({ enumerated: weekDays, returnNullOnErrors: false });
v.enumeratedKey('e1', 'MON')
 .enumeratedKey('e2', 4)             // fail: 4 is a value, not a key
 .enumeratedKey('e3', weekDays.THU)  // fail: this resolves to 3, which is not a key
 .enumeratedKey('e4', 'SUN')
 .enumeratedKey('e5', 'Friday')      // fail: Ok this has nothing to do here...
 .enumeratedKey('e6', 'fri');        // fail: the key is defined as an upper case string
v.valid(); // { e1: 'MON', e4: 'SUN' }


This validator works the same that enumeratedKey, checking that the data is a key of the object, but returning its associated value instead of the key itself.

var weekDays = { MON: 0, TUE: 1, WED: 2, THU: 3, FRI: 4, SAT: 5, SUN: 6 };
var v = new Validator({ enumerated: weekDays, returnNullOnErrors: false });
v.enumeratedKeyValue('e1', 'MON')
 .enumeratedKeyValue('e2', 4)             // fail: 4 is a value, not a key
 .enumeratedKeyValue('e3', weekDays.THU)  // fail: this resolves to 3, which is not a key
 .enumeratedKeyValue('e4', 'SUN')
 .enumeratedKeyValue('e5', 'Friday')      // fail: Ok this has nothing to do here...
 .enumeratedKeyValue('e6', 'fri');        // fail: the key is defined as an upper case string
v.valid(); // { e1: 0, e4: 6 }


Validates data to be a correct JSON definition (using JSON.parse). Doesn't accept any option, and returns the parsed JavaScript data.

Note that functions and NaN are not parseable by JSON, so they are not supported, and will fail the validation.

var v = new Validator();
v.json('data', '[1,2,3]');
v.valid().data[1]; // 2

List of default aliases


Alias using str, with default options to reject empty strings.

var v = new Validator({ returnNullOnErrors: false });
v.notEmptyStr('s1', 'abcd')
 .notEmptyStr('s2', ' ')
 .notEmptyStr('s3', '')
 .notEmptyStr('n1', 2);
v.valid();   // { s1: 'abcd', s2: ' ' }
v.errors();  // { s3: '', n1: 2 }


Alias using num, to accept only integers greater than 0

var v = new Validator({ returnNullOnErrors: false });
v.positiveInt('n1', '123')
 .positiveInt('n2', 123)
 .positiveInt('n3', 1)
 .positiveInt('n4', 0)
 .positiveInt('n5', -1)
 .positiveInt('f1', 1.5)
 .positiveInt('f2', '6.5')
 .positiveInt('f3', 0.5)
 .positiveInt('f4', -1.5);
v.valid();   // { n1: 123, n2: 123, n3: 1, f1: 1, f2: 6 }
v.errors();  // { n4: 0, n5: -1, f3: 0.5, f4: -1.5 }

Defining custom validators

If you need a more complex validator, you can create your own too!

They can be created as global validators (defined in the prototype) with Validator.addValidator or locally (defined in an instance v) with v.addValidator

A validator is just a function accepting two parameters and returning an object: (data, options) => { data, valid }

  • input:
    • data is the data to validate
    • options is an object with the options specified when creating the validator or calling the method
  • output:
    • data is the canonized data (type casting, etc.)
    • valid is a Boolean saying if the data passes the validation

It's easier to understand with examples:

This validator will pass everything but the number 0 (and making use of the strict option)

// validator definition
function allButZero(data, options) {
  return {
    data: data,
    valid: (options.strict && data !== 0) || (!options.strict && data!= 0)
// validator addition (as a global definition called allButZero)
Validator.addValidator('allButZero', allButZero);
// validator usage:
= new Validator({ returnNullOnErrors: false, strict: false });
v.allButZero('n1', 1)
 .allButZero('n2', 0)
 .allButZero('n3', "0")
 .allButZero('n4', "0", { strict: true });
v.valid();  // { n1: 1, n4: "0" }
v.errors(); // { n2: 0, n3: "0" }

This other validator will accept only a list of comma-separated numbers whose addition is an even number.

If options.odd is true, it will pass the validation if the total is an odd number instead of even.

It will also convert the data to the said total.

// validator definition
function exampleValidator(data, options) {
  var ok = true;
  var total = 0;
  var list;
  if (typeof data !== 'string') {
    ok = false;
  } else {
    list = data.split(',');
    list.every(function(n) {
      n = parseInt(n);
      if (isNaN(n)) {
        ok = false;
        return false;
      total += n;
      return true;
    if (ok) {
      ok = total % 2 === (options.odd ? 1 : 0);
  return {
    data: total,
    valid: ok,
// validator addition (as a global definition called sumEven)
Validator.addValidator('sumEven', exampleValidator);
// validator usage:
= new Validator({ returnNullOnErrors: false });
v.sumEven('pass', '1,3,-1,5')             // 1 + 3 - 1 + 5 = 8 (even number: ok)
 .sumEven('odd', '1,2,4', { odd: true })  // 1 + 2 + 4 = 7 (odd number: ok in this case)
 .sumEven('fail', '-3,2,8');              // -3 + 2 + 8 = 7 (odd number: fail)
v.valid();  // { pass: 8, odd: 7 }
v.errors(); // { fail: '-3,2,8' }

You can see more examples in definitions.js

Defining custom aliases

You can define your own aliases to call existing validators (or other aliases) with predefined options.

They can be created as global validators (defined in the prototype) with Validator.addAlias or locally (defined in an instance v) with v.addAlias

var Validator = require('bulk-validator').Validator;
// define a global validator for phone numbers
// (in Japan phone numbers are like XXX-XXXX-XXXX)
var alias = 'phone';
var validator = 'str';
var options = { regExp: /^\d{3}-\d{4}-\d{4}$/ };
// using the static function addAlias define the validator in the prototype
Validator.addAlias(alias, validator, options);
// now we can use it like this:
var v1 = new Validator();
var v2 = new Validator();'foo', '080-1234-5678') // this will validate
  .phone('bar', '1234-5678');    // this won't validate
typeof; // function
typeof; // function
// we can create a local validator too, like this:
v1.addAlias('int', 'num', { integer: true });
// it won't be defined in the Validator.prototype
typeof; // 'function'
typeof; // 'undefined'

You can see more examples in aliases.js

Defining and using schemas

A schema is nothing else than a set of validations. It's very useful when trying to validate the same set of data everytime (i.e. data to be stored in a database, or data for a data model coming from user input).

As the validators and aliases, a schema can be defined locally to a Validator instance, or globally to the Validator class itself.

var schemaDefinition = {
  foo: {
    validator: 'str'
  bar: {
    validator: 'num',
    options: { defaultValue: 0 },
var schemaOptions = {
  optional: true,
// defining a local validator schema
var v1 = new Validator();
var v2 = new Validator();
v1.addSchema('local-schema', schemaDefinition, schemaOptions);
// defining a global validator schema
Validator.addSchema('global-schema', schemaDefinition, schemaOptions);
// now we can use the schema like this:
var data = {
  foo: 'some text',
  bar: 123,
// we can use the previously defined local schema in v1
v1.schema('local-schema', data);
v1.valid(); // { foo: 'some text', bar: 123 }
// also, the global one in v1 and v2
v1.schema('global-schema', data);
v2.schema('global-schema', data);
// but using a local schema in a different instance will throw an error
v2.schema('local-schema', data); // error
// note that everytime we call .schema(), a .reset() call is done internally:
v1.schema('local-schema', { foo: 'abc', bar: 123 });
v1.valid(); // { foo: 'abc', bar: 123 }
v1.schema('local-schema', { foo: 'abc' });
v1.valid(); // { foo: 'abc', bar: 0 }
// extra local options can also be passed to schema validations
v1.schema('local-schema', { foo: 'abc', bar: '123' }, { canonize: false });
v1.valid(); // { foo: 'abc', bar: '123' }

Running tests

Install dev dependencies

npm install -d && npm test

Change log


  • Added preTransform and postTransform optional callbacks to validators.
  • Fixed: default options behavior. Default options now get applied properly even if they change after defining a validator.
  • Fixed: allowOverwriteValidator now works for aliases and schemas too.
  • Fixed: Schemas now use properly options specified at the definition time, and local options for each property validation.
  • Added new schema options: includeExternal and externalShouldFail.
  • Added local options for schema validations (as a new 3rd parameter).


npm i bulk-validator

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