fastest-validator

fastest-validator

:zap: The fastest JS validator library for NodeJS | Browser | Deno.

Key features

• blazing fast! Really!
• 20+ built-in validators
• many sanitizations
• custom validators & aliases
• nested objects & array handling
• strict object validation
• multiple validators
• customizable error messages
• programmable error object
• no dependencies
• unit tests & 100% coverage

How fast?

Very fast! 8 million validations/sec (on Intel i7-4770K, Node.JS: 12.14.1)

√ validate                            8,678,752 rps

Compared to other popular libraries:

50x faster than Joi.

Would you like to test it?

$ git clone https://github.com/icebob/fastest-validator.git
$ cd fastest-validator
$ npm install
$ npm run bench

Approach

In order to achieve lowest cost/highest performance redaction fastest-validator creates and compiles functions using the Function constructor. It's important to distinguish this from the dangers of a runtime eval, no user input is involved in creating the validation schema that compiles into the function. This is as safe as writing code normally and having it compiled by V8 in the usual way.

Installation

NPM

You can install it via NPM.

$ npm i fastest-validator --save

or

$ yarn add fastest-validator

Usage

Validate

The first step is to compile the schema to a compiled "checker" function. After that, to validate your object, just call this "checker" function.

This method is the fastest.

const Validator = require("fastest-validator");

const v = new Validator();

const schema = {
    id: { type: "number", positive: true, integer: true },
    name: { type: "string", min: 3, max: 255 },
    status: "boolean" // short-hand def
};

const check = v.compile(schema);

console.log("First:", check({ id: 5, name: "John", status: true }));
// Returns: true

console.log("Second:", check({ id: 2, name: "Adam" }));
/* Returns an array with errors:
    [
        {
            type: 'required',
            field: 'status',
            message: 'The \'status\' field is required!'
        }
    ]
*/

Try it on Repl.it

Browser usage

<script src="https://unpkg.com/fastest-validator"></script>

const v = new FastestValidator();

const schema = {
    id: { type: "number", positive: true, integer: true },
    name: { type: "string", min: 3, max: 255 },
    status: "boolean" // short-hand def
};

const check = v.compile(schema);

console.log(check({ id: 5, name: "John", status: true }));
// Returns: true

Deno usage

With esm.sh, now Typescript is supported

import FastestValidator from "https://esm.sh/fastest-validator@1"

const v = new FastestValidator();
const check = v.compile({
    name: "string",
    age: "number",
});

console.log(check({ name: "Erf", age: 18 })); //true

Supported frameworks

• Moleculer: Natively supported
• Fastify: By using fastify-fv
• Express: By using fastest-express-validator

Optional, Required & Nullable fields

Optional

Every field in the schema will be required by default. If you'd like to define optional fields, set optional: true.

const schema = {
    name: { type: "string" }, // required
    age: { type: "number", optional: true }
}

const check = v.compile(schema);

check({ name: "John", age: 42 }); // Valid
check({ name: "John" }); // Valid
check({ age: 42 }); // Fail because name is required

Nullable

If you want disallow undefined value but allow null value, use nullable instead of optional.

const schema = {
    age: { type: "number", nullable: true }
}

const check = v.compile(schema);

check({ age: 42 }); // Valid
check({ age: null }); // Valid
check({ age: undefined }); // Fail because undefined is disallowed
check({}); // Fail because undefined is disallowed

Nullable and default values

null is a valid input for nullable fields that has default value.

const schema = {
   about: { type: "string", nullable: true, default: "Hi! I'm using javascript" }
}

const check = v.compile(schema)

const object1 = { about: undefined }
check(object1) // Valid
object1.about // is "Hi! I'm using javascript"

const object2 = { about: null }
check(object2) // valid
object2.about // is null

check({ about: "Custom" }) // Valid

Strict validation

Object properties which are not specified on the schema are ignored by default. If you set the $$strict option to true any additional properties will result in an strictObject error.

const schema = {
    name: { type: "string" }, // required
    $$strict: true // no additional properties allowed
}

const check = v.compile(schema);

check({ name: "John" }); // Valid
check({ name: "John", age: 42 }); // Fail

Remove additional fields

To remove the additional fields in the object, set $$strict: "remove".

Multiple validators

It is possible to define more validators for a field. In this case, only one validator needs to succeed for the field to be valid.

const schema = {
    cache: [
        { type: "string" },
        { type: "boolean" }
    ]
}

const check = v.compile(schema);

check({ cache: true }); // Valid
check({ cache: "redis://" }); // Valid
check({ cache: 150 }); // Fail

Root element schema

Basically the validator expects that you want to validate a Javascript object. If you want others, you can define the root level schema, as well. In this case set the $$root: true property.

Example to validate a string variable instead of object

const schema = {
    $$root: true,
    type: "string", 
    min: 3, 
    max: 6
};

const check = v.compile(schema);

check("John"); // Valid
check("Al"); // Fail, too short.

Sanitizations

The library contains several sanitizers. Please note, the sanitizers change the original checked object.

Default values

The most common sanitizer is the default property. With it, you can define a default value for all properties. If the property value is null* or undefined, the validator set the defined default value into the property.

Static Default value example:

const schema = {
    roles: { type: "array", items: "string", default: ["user"] },
    status: { type: "boolean", default: true },
};

const check = v.compile(schema);

const obj = {}

check(obj); // Valid
console.log(obj);
/*
{
    roles: ["user"],
    status: true
}
*/

Dynamic Default value: Also you can use dynamic default value by defining a function that returns a value. For example, in the following code, if createdAt field not defined in object`, the validator sets the current time into the property:

const schema = {
    createdAt: {
        type: "date",
        default: (schema, field, parent, context) => new Date()
    }
};

const check = v.compile(schema);

const obj = {}

check(obj); // Valid
console.log(obj);
/*
{
    createdAt: Date(2020-07-25T13:17:41.052Z)
}
*/

Shorthand definitions

You can use string-based shorthand validation definitions in the schema.

const schema = {
    password: "string|min:6",
    age: "number|optional|integer|positive|min:0|max:99", // additional properties
    state: ["boolean", "number|min:0|max:1"] // multiple types
}

Array of X

const schema = {
    foo: "string[]" // means array of string
}

const check = v.compile(schema);

check({ foo: ["bar"] }) // true

Nested objects

const schema = {
   dot: {
      $$type: "object",
      x: "number",  // object props here
      y: "number",  // object props here
   }, 
   circle: {
      $$type: "object|optional", // using other shorthands
      o: {
         $$type: "object",
         x: "number",
         y: "number",
      },
      r: "number"
   }
};

Alias definition

You can define custom aliases.

v.alias('username', {
    type: 'string',
    min: 4,
    max: 30
    // ...
});

const schema = {
    username: "username|max:100", // Using the 'username' alias
    password: "string|min:6",
}

Default options

You can set default rule options.

const v = new FastestValidator({
    defaults: {
        object: {
            strict: "remove"
        }
    }
});

Built-in validators

any

This does not do type validation. Accepts any types.

const schema = {
    prop: { type: "any" }
}

const check = v.compile(schema)

check({ prop: true }); // Valid
check({ prop: 100 }); // Valid
check({ prop: "John" }); // Valid

array

This is an Array validator.

Simple example with strings:

const schema = {
    roles: { type: "array", items: "string" }
}
const check = v.compile(schema)

check({ roles: ["user"] }); // Valid
check({ roles: [] }); // Valid
check({ roles: "user" }); // Fail

Example with only positive numbers:

const schema = {
    list: { type: "array", min: 2, items: {
        type: "number", positive: true, integer: true
    } }
}
const check = v.compile(schema)

check({ list: [2, 4] }); // Valid
check({ list: [1, 5, 8] }); // Valid
check({ list: [1] }); // Fail (min 2 elements)
check({ list: [1, -7] }); // Fail (negative number)

Example with an object list:

const schema = {
    users: { type: "array", items: {
        type: "object", props: {
            id: { type: "number", positive: true },
            name: { type: "string", empty: false },
            status: "boolean"
        }
    } }
}
const check = v.compile(schema)

check({
    users: [
        { id: 1, name: "John", status: true },
        { id: 2, name: "Jane", status: true },
        { id: 3, name: "Bill", status: false }
    ]
}); // Valid

Example for enum:

const schema = {
    roles: { type: "array", items: "string", enum: [ "user", "admin" ] }
}

const check = v.compile(schema)

check({ roles: ["user"] }); // Valid
check({ roles: ["user", "admin"] }); // Valid
check({ roles: ["guest"] }); // Fail

Example for unique:

const schema = {
    roles: { type: "array", unique: true }
}
const check = v.compile(schema);

check({ roles: ["user"] }); // Valid
check({ roles: [{role:"user"},{role:"admin"},{role:"user"}] }); // Valid
check({ roles: ["user", "admin", "user"] }); // Fail
check({ roles: [1, 2, 1] }); // Fail

Properties

Property	Default	Description
empty	true	If true, the validator accepts an empty array [].
min	null	Minimum count of elements.
max	null	Maximum count of elements.
length	null	Fix count of elements.
contains	null	The array must contain this element too.
unique	null	The array must be unique (array of objects is always unique).
enum	null	Every element must be an element of the enum array.
items	null	Schema for array items.

boolean

This is a Boolean validator.

const schema = {
    status: { type: "boolean" }
}
const check = v.compile(schema);

check({ status: true }); // Valid
check({ status: false }); // Valid
check({ status: 1 }); // Fail
check({ status: "true" }); // Fail

Properties

Property	Default	Description
convert	false	if true and the type is not Boolean, it will be converted. 1, "true", "1", "on" will be true. 0, "false", "0", "off" will be false. It's a sanitizer, it will change the value in the original object.

Example for convert:

const schema = {
    status: { type: "boolean", convert: true}
};

const check = v.compile(schema);

check({ status: "true" }); // Valid

class

This is a Class validator to check the value is an instance of a Class.

const schema = {
    rawData: { type: "class", instanceOf: Buffer }
}
const check = v.compile(schema);

check({ rawData: Buffer.from([1, 2, 3]) }); // Valid
check({ rawData: 100 }); // Fail

Properties

Property	Default	Description
instanceOf	null	Checked Class.

currency

This is a Currency validator to check if the value is a valid currency string.

const schema = {
    money_amount: { type: "currency", currencySymbol: '$' }
}
const check = v.compile(schema);


check({ money_amount: '$12.99'}); // Valid
check({ money_amount: '$0.99'}); // Valid
check({ money_amount: '$12,345.99'}); // Valid
check({ money_amount: '$123,456.99'}); // Valid

check({ money_amount: '$1234,567.99'}); // Fail
check({ money_amount: '$1,23,456.99'}); // Fail
check({ money_amount: '$12,34.5.99' }); // Fail

Properties

Property	Default	Description
currencySymbol	null	The currency symbol expected in string (as prefix).
symbolOptional	false	Toggle to make the symbol optional in string, although, if present it would only allow the currencySymbol.
thousandSeparator	,	Thousand place separator character.
decimalSeparator	.	Decimal place character.
customRegex	null	Custom regular expression, to validate currency strings (For eg: /[0-9]*/g).

date

This is a Date validator.

const schema = {
    dob: { type: "date" }
}
const check = v.compile(schema);

check({ dob: new Date() }); // Valid
check({ dob: new Date(1488876927958) }); // Valid
check({ dob: 1488876927958 }); // Fail

Properties

Property	Default	Description
convert	false	if true and the type is not Date, try to convert with new Date(). It's a sanitizer, it will change the value in the original object.

Example for convert:

const schema = {
    dob: { type: "date", convert: true}
};

const check = v.compile(schema);

check({ dob: 1488876927958 }, ); // Valid

email

This is an e-mail address validator.

const schema = {
    email: { type: "email" }
}
const check = v.compile(schema);


check({ email: "[e-mail]" }); // Valid
check({ email: "[e-mail]" }); // Valid
check({ email: "abc@gmail" }); // Fail

Properties

Property	Default	Description
empty	false	If true, the validator accepts an empty array "".
mode	quick	Checker method. Can be quick or precise.
normalize	false	Normalize the e-mail address (trim & lower-case). It's a sanitizer, it will change the value in the original object.
min	null	Minimum value length.
max	null	Maximum value length.

enum

This is an enum validator.

const schema = {
    sex: { type: "enum", values: ["male", "female"] }
}
const check = v.compile(schema);


check({ sex: "male" }); // Valid
check({ sex: "female" }); // Valid
check({ sex: "other" }); // Fail

Properties

Property	Default	Description
values	null	The valid values.

equal

This is an equal value validator. It checks a value with a static value or with another property.

Example with static value:

const schema = {
    agreeTerms: { type: "equal", value: true, strict: true } // strict means `===`
}
const check = v.compile(schema);

check({ agreeTerms: true }); // Valid
check({ agreeTerms: false }); // Fail

Example with other field:

const schema = {
    password: { type: "string", min: 6 },
    confirmPassword: { type: "equal", field: "password" }
}
const check = v.compile(schema);

check({ password: "123456", confirmPassword: "123456" }); // Valid
check({ password: "123456", confirmPassword: "pass1234" }); // Fail

Properties

Property	Default	Description
value	undefined	The expected value. It can be any primitive types.
strict	false	if true, it uses strict equal === for checking.

forbidden

This validator returns an error if the property exists in the object.

const schema = {
    password: { type: "forbidden" }
}
const check = v.compile(schema);


check({ user: "John" }); // Valid
check({ user: "John", password: "pass1234" }); // Fail

Properties

Property	Default	Description
remove	false	If true, the value will be removed in the original object. It's a sanitizer, it will change the value in the original object.

Example for remove:

const schema = {
    user: { type: "string" },
    token: { type: "forbidden", remove: true }
};
const check = v.compile(schema);


const obj = {
    user: "John",
    token: "123456"
}

check(obj); // Valid
console.log(obj);
/*
{
    user: "John",
    token: undefined
}
*/

function

This a Function type validator.

const schema = {
    show: { type: "function" }
}
const check = v.compile(schema);


check({ show: function() {} }); // Valid
check({ show: Date.now }); // Valid
check({ show: "function" }); // Fail

luhn

This is an Luhn validator. Luhn algorithm checksum Credit Card numbers, IMEI numbers, National Provider Identifier numbers and others

const schema = {
    cc: { type: "luhn" }
}
const check = v.compile(schema);

check({ cc: "452373989901198" }); // Valid
check({ cc: 452373989901198 }); // Valid
check({ cc: "4523-739-8990-1198" }); // Valid
check({ cc: "452373989901199" }); // Fail

mac

This is an MAC addresses validator.

const schema = {
    mac: { type: "mac" }
}
const check = v.compile(schema);

check({ mac: "01:C8:95:4B:65:FE" }); // Valid
check({ mac: "01:c8:95:4b:65:fe"); // Valid
check({ mac: "01C8.954B.65FE" }); // Valid
check({ mac: "01c8.954b.65fe"); // Valid
check({ mac: "01-C8-95-4B-65-FE" }); // Valid
check({ mac: "01-c8-95-4b-65-fe" }); // Valid
check({ mac: "01C8954B65FE" }); // Fail

multi

This is a multiple definitions validator.

const schema = {
    status: { type: "multi", rules: [
        { type: "boolean" },
        { type: "number" }
    ], default: true }
}
const check = v.compile(schema);

check({ status: true }); // Valid
check({ status: false }); // Valid
check({ status: 1 }); // Valid
check({ status: 0 }); // Valid
check({ status: "yes" }); // Fail

Shorthand multiple definitions:

const schema = {
    status: [
        "boolean",
        "number"
    ]
}
const check = v.compile(schema);

check({ status: true }); // Valid
check({ status: false }); // Valid
check({ status: 1 }); // Valid
check({ status: 0 }); // Valid
check({ status: "yes" }); // Fail

number

This is a Number validator.

const schema = {
    age: { type: "number" }
}
const check = v.compile(schema);

check({ age: 123 }); // Valid
check({ age: 5.65 }); // Valid
check({ age: "100" }); // Fail

Properties

Property	Default	Description
min	null	Minimum value.
max	null	Maximum value.
equal	null	Fixed value.
notEqual	null	Can't be equal to this value.
integer	false	The value must be a non-decimal value.
positive	false	The value must be greater than zero.
negative	false	The value must be less than zero.
convert	false	if true and the type is not Number, it's converted with Number(). It's a sanitizer, it will change the value in the original object.

object

This is a nested object validator.

const schema = {
    address: { type: "object", strict: true, props: {
        country: { type: "string" },
        city: "string", // short-hand
        zip: "number" // short-hand
    } }
}
const check = v.compile(schema);

check({
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345
    }
}); // Valid

check({
    address: {
        country: "Italy",
        city: "Rome"
    }
}); // Fail ("The 'address.zip' field is required!")

check({
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345,
        state: "IT"
    }
}); // Fail ("The 'address.state' is an additional field!")

Properties

Property	Default	Description
strict	false	If true any properties which are not defined on the schema will throw an error. If remove all additional properties will be removed from the original object. It's a sanitizer, it will change the original object.
minProps	null	If set to a number N, will throw an error if the object has fewer than N properties.
maxProps	null	If set to a number N, will throw an error if the object has more than N properties.

schema = {
    address: { type: "object", strict: "remove", props: {
        country: { type: "string" },
        city: "string", // short-hand
        zip: "number" // short-hand
    } }
}

let obj = {
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345,
        state: "IT"
    }
};
const check = v.compile(schema);

check(obj); // Valid
console.log(obj);
/*
{
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345
    }   
}
*/

schema = {
  address: {
    type: "object",
    minProps: 2,
    props: {
      country: { type: "string" },
      city: { type: "string", optional: true },
      zip: { type: "number", optional: true }
    }
  }
}
const check = v.compile(schema);


obj = {
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345,
        state: "IT"
    }
}

check(obj); // Valid

obj = {
    address: {
        country: "Italy",
    }
}

check(obj); // Fail
// [
//   {
//     type: 'objectMinProps',
//     message: "The object 'address' must contain at least 2 properties.",
//     field: 'address',
//     expected: 2,
//     actual: 1
//   }
// ]

record

This validator allows to check an object with arbitrary keys.

const schema = {
    surnameGroups: {
        type: 'record',
        key: { type: 'string', alpha: true },
        value: { type: 'array', items: 'string' }
    }
};
const check = v.compile(schema);

check({ surnameGroups: { Doe: ['Jane', 'John'], Williams: ['Bill'] } }); // Valid
check({ surnameGroups: { Doe1: ['Jane', 'John'] } }); // Fail
check({ surnameGroups: { Doe: [1, 'Jane'] } }); // Fail

Properties

Property	Default	Description
key	string	Key validation rule (It is reasonable to use only the string rule).
value	any	Value validation rule.

string

This is a String validator.

const schema = {
    name: { type: "string" }
}
const check = v.compile(schema);

check({ name: "John" }); // Valid
check({ name: "" }); // Valid
check({ name: 123 }); // Fail

Properties

Property	Default	Description
empty	true	If true, the validator accepts an empty string "".
min	null	Minimum value length.
max	null	Maximum value length.
length	null	Fixed value length.
pattern	null	Regex pattern.
contains	null	The value must contain this text.
enum	null	The value must be an element of the enum array.
alpha	null	The value must be an alphabetic string.
numeric	null	The value must be a numeric string.
alphanum	null	The value must be an alphanumeric string.
alphadash	null	The value must be an alphabetic string that contains dashes.
hex	null	The value must be a hex string.
singleLine	null	The value must be a single line string.
base64	null	The value must be a base64 string.
trim	null	If true, the value will be trimmed. It's a sanitizer, it will change the value in the original object.
trimLeft	null	If true, the value will be left trimmed. It's a sanitizer, it will change the value in the original object.
trimRight	null	If true, the value will be right trimmed. It's a sanitizer, it will change the value in the original object.
padStart	null	If it's a number, the value will be left padded. It's a sanitizer, it will change the value in the original object.
padEnd	null	If it's a number, the value will be right padded. It's a sanitizer, it will change the value in the original object.
padChar	" "	The padding character for the padStart and padEnd.
lowercase	null	If true, the value will be lower-cased. It's a sanitizer, it will change the value in the original object.
uppercase	null	If true, the value will be upper-cased. It's a sanitizer, it will change the value in the original object.
localeLowercase	null	If true, the value will be locale lower-cased. It's a sanitizer, it will change the value in the original object.
localeUppercase	null	If true, the value will be locale upper-cased. It's a sanitizer, it will change the value in the original object.
convert	false	if true and the type is not a String, it's converted with String(). It's a sanitizer, it will change the value in the original object.

Sanitization example

const schema = {
    username: { type: "string", min: 3, trim: true, lowercase: true}
}
const check = v.compile(schema);

const obj = {
    username: "   Icebob  "
};

check(obj); // Valid
console.log(obj);
/*
{
    username: "icebob"
}
*/

tuple

This validator checks if a value is an Array with the elements order as described by the schema.

Simple example:

const schema = { list: "tuple" };
const check = v.compile(schema);

check({ list: [] }); // Valid
check({ list: [1, 2] }); // Valid
check({ list: ["RON", 100, true] }); // Valid
check({ list: 94 }); // Fail (not an array)

Example with items:

const schema = {
    grade: { type: "tuple", items: ["string", "number"] }
}
const check = v.compile(schema);

check({ grade: ["David", 85] }); // Valid
check({ grade: [85, "David"] }); // Fail (wrong position)
check({ grade: ["Cami"] }); // Fail (require 2 elements)

Example with a more detailed schema:

const schema = {
    location: { type: "tuple", items: [
        "string",
        { type: "tuple", empty: false, items: [
            { type: "number", min: 35, max: 45 },
            { type: "number", min: -75, max: -65 }
        ] }
    ] }
}
const check = v.compile(schema);

check({ location: ['New York', [40.7127281, -74.0060152]] }); // Valid
check({ location: ['New York', [50.0000000, -74.0060152]] }); // Fail
check({ location: ['New York', []] }); // Fail (empty array)

Properties

Property	Default	Description
empty	true	If true, the validator accepts an empty array [].
items	undefined	Exact schema of the value items

url

This is an URL validator.

const schema = {
    url: { type: "url" }
}
const check = v.compile(schema);

check({ url: "http://google.com" }); // Valid
check({ url: "https://github.com/icebob" }); // Valid
check({ url: "www.facebook.com" }); // Fail

Properties

Property	Default	Description
empty	false	If true, the validator accepts an empty string "".

uuid

This is an UUID validator.

const schema = {
    uuid: { type: "uuid" }
}
const check = v.compile(schema);

check({ uuid: "00000000-0000-0000-0000-000000000000" }); // Valid Nil UUID
check({ uuid: "10ba038e-48da-487b-96e8-8d3b99b6d18a" }); // Valid UUIDv4
check({ uuid: "9a7b330a-a736-51e5-af7f-feaf819cdc9f" }); // Valid UUIDv5
check({ uuid: "10ba038e-48da-487b-96e8-8d3b99b6d18a", version: 5 }); // Fail

Properties

Property	Default	Description
version	null	UUID version in range 0-6. The null disables version checking.

objectID

You can validate BSON/MongoDB ObjectID's

const  { ObjectID } = require("mongodb") // or anywhere else 

const schema = {
    id: {
        type: "objectID",
        ObjectID // passing the ObjectID class
    }  
}
const check = v.compile(schema);

check({ id: "5f082780b00cc7401fb8e8fc" }) // ok
check({ id: new ObjectID() }) // ok
check({ id: "5f082780b00cc7401fb8e8" }) // Error

Pro tip: By using defaults props for objectID rule, No longer needed to pass ObjectID class in validation schema:

const  { ObjectID } = require("mongodb") // or anywhere else 

const v = new Validator({
    defaults: {
        objectID: {
            ObjectID
        }
    }
})

const schema = {
    id: "objectID" 
}

Properties

Property	Default	Description
convert	false	If true, the validator converts ObjectID HexString representation to ObjectID instance, if hexString the validator converts to HexString

Custom validator

You can also create your custom validator.

const v = new Validator({
    messages: {
        // Register our new error message text
        evenNumber: "The '{field}' field must be an even number! Actual: {actual}"
    }
});

// Register a custom 'even' validator
v.add("even", function({ schema, messages }, path, context) {
    return {
        source: `
            if (value % 2 != 0)
                ${this.makeError({ type: "evenNumber",  actual: "value", messages })}

            return value;
        `
    };
});

const schema = {
    name: { type: "string", min: 3, max: 255 },
    age: { type: "even" }
};
const check = v.compile(schema);

console.log(check({ name: "John", age: 20 }, schema));
// Returns: true

console.log(check({ name: "John", age: 19 }, schema));
/* Returns an array with errors:
    [{
        type: 'evenNumber',
        expected: null,
        actual: 19,
        field: 'age',
        message: 'The \'age\' field must be an even number! Actual: 19'
    }]
*/

Or you can use the custom type with an inline checker function:

const v = new Validator({
    useNewCustomCheckerFunction: true, // using new version
    messages: {
        // Register our new error message text
        weightMin: "The weight must be greater than {expected}! Actual: {actual}"
    }
});

const schema = {
    name: { type: "string", min: 3, max: 255 },
    weight: {
        type: "custom",
        minWeight: 10,
        check(value, errors, schema) {
            if (value < minWeight) errors.push({ type: "weightMin", expected: schema.minWeight, actual: value });
            if (value > 100) value = 100
            return value
        }
    }
};
const check = v.compile(schema);

console.log(check({ name: "John", weight: 50 }, schema));
// Returns: true

console.log(check({ name: "John", weight: 8 }, schema));
/* Returns an array with errors:
    [{
        type: 'weightMin',
        expected: 10,
        actual: 8,
        field: 'weight',
        message: 'The weight must be greater than 10! Actual: 8'
    }]
*/
const o = { name: "John", weight: 110 }
console.log(check(o, schema));
/* Returns: true
   o.weight is 100
*/

Please note: the custom function must return the value. It means you can also sanitize it.

Custom validation for built-in rules

You can define a custom function in the schema for built-in rules. With it you can extend any built-in rules.

const v = new Validator({
    useNewCustomCheckerFunction: true, // using new version
    messages: {
        // Register our new error message text
        phoneNumber: "The phone number must be started with '+'!"
    }
});

const schema = {
    name: { type: "string", min: 3, max: 255 },
    phone: { type: "string", length: 15, custom: (v, errors) => {
            if (!v.startsWith("+")) errors.push({ type: "phoneNumber" })
            return v.replace(/[^\d+]/g, ""); // Sanitize: remove all special chars except numbers
        }
    }	
};
const check = v.compile(schema);


console.log(check({ name: "John", phone: "[phone]" }));
// Returns: true

console.log(check({ name: "John", phone: "36-70-123-4567" }));
/* Returns an array with errors:
    [{
        message: "The phone number must be started with '+'!",
        field: 'phone',
        type: 'phoneNumber'
    }]
*/

Please note: the custom function must return the value. It means you can also sanitize it.

Asynchronous custom validations

You can also use async custom validators. This can be useful if you need to check something in a database or in a remote location. In this case you should use async/await keywords, or return a Promise in the custom validator functions.

This implementation uses async/await keywords. So this feature works only on environments which supports async/await:

• Chrome > 55
• Firefox > 52
• Edge > 15
• NodeJS > 8.x (or 7.6 with harmony)
• Deno (all versions)

To enable async mode, you should set $$async: true in the root of your schema.

Example with custom checker function

const v = new Validator({
    useNewCustomCheckerFunction: true, // using new version
    messages: {
        // Register our new error message text
        unique: "The username is already exist"
    }
});

const schema = {
    $$async: true,
    name: { type: "string" },
    username: {
        type: "string",
        min: 2,
        custom: async (v, errors) => {
            // E.g. checking in the DB that the value is unique.
            const res = await DB.checkUsername(v);
            if (!res) 
                errors.push({ type: "unique", actual: value });

            return v;
        }
    }
    // ...
};

const check = v.compile(schema);

const res = await check(user);
console.log("Result:", res);

The compiled check function contains an async property, so you can check if it returns a Promise or not.

const check = v.compile(schema);
console.log("Is async?", check.async);

Meta information for custom validators

You can pass any extra meta information for the custom validators which is available via context.meta.

const schema = {
    name: { type: "string", custom: (value, errors, schema, name, parent, context) => {
        // Access to the meta
        return context.meta.a;
    } },
};
const check = v.compile(schema);

const res = check(obj, {
    // Passes meta information
    meta: { a: "from-meta" }
});

Custom error messages (l10n)

You can set your custom messages in the validator constructor.

const Validator = require("fastest-validator");
const v = new Validator({
    messages: {
        stringMin: "A(z) '{field}' mező túl rövid. Minimum: {expected}, Jelenleg: {actual}",
        stringMax: "A(z) '{field}' mező túl hosszú. Minimum: {expected}, Jelenleg: {actual}"
    }
});

const schema = {
    name: { type: "string", min: 6 }
}
const check = v.compile(schema);

check({ name: "John" });
/* Returns:
[
    {
        type: 'stringMin',
        expected: 6,
        actual: 4,
        field: 'name',
        message: 'A(z) \'name\' mező túl rövid. Minimum: 6, Jelenleg: 4'
    }
]
*/

Personalised Messages

Sometimes the standard messages are too generic. You can customize messages per validation type per field:

const Validator = require("fastest-validator");
const v = new Validator();
const schema = {
    firstname: {
        type: "string",
        min: 6,
        messages: {
            string: "Please check your firstname",
            stringMin: "Your firstname is too short"
        }
    },
    lastname: {
        type: "string",
        min: 6,
        messages: {
            string: "Please check your lastname",
            stringMin: "Your lastname is too short"
        }
    }
}
const check = v.compile(schema);

check({ firstname: "John", lastname: 23 });
/* Returns:
[
    {
        type: 'stringMin',
        expected: 6,
        actual: 4,
        field: 'firstname',
        message: 'Your firstname is too short'
    },
    {
        type: 'string',
        expected: undefined,
        actual: undefined,
        field: 'lastname',
        message: 'Please check your lastname'
    }
]
*/

Plugins

You can apply plugins:

// Plugin Side
function myPlugin(validator){
    // you can modify validator here
    // e.g.: validator.add(...)
}

// Validator Side
const v = new Validator();
v.plugin(myPlugin)

Message types

Name	Default text
required	The '{field}' field is required.
string	The '{field}' field must be a string.
stringEmpty	The '{field}' field must not be empty.
stringMin	The '{field}' field length must be greater than or equal to {expected} characters long.
stringMax	The '{field}' field length must be less than or equal to {expected} characters long.
stringLength	The '{field}' field length must be {expected} characters long.
stringPattern	The '{field}' field fails to match the required pattern.
stringContains	The '{field}' field must contain the '{expected}' text.
stringEnum	The '{field}' field does not match any of the allowed values.
stringNumeric	The '{field}' field must be a numeric string.
stringAlpha	The '{field}' field must be an alphabetic string.
stringAlphanum	The '{field}' field must be an alphanumeric string.
stringAlphadash	The '{field}' field must be an alphadash string.
stringHex	The '{field}' field must be a hex string.
stringSingleLine	The '{field}' field must be a single line string.
stringBase64	The '{field}' field must be a base64 string.
number	The '{field}' field must be a number.
numberMin	The '{field}' field must be greater than or equal to {expected}.
numberMax	The '{field}' field must be less than or equal to {expected}.
numberEqual	The '{field}' field must be equal to {expected}.
numberNotEqual	The '{field}' field can't be equal to {expected}.
numberInteger	The '{field}' field must be an integer.
numberPositive	The '{field}' field must be a positive number.
numberNegative	The '{field}' field must be a negative number.
array	The '{field}' field must be an array.
arrayEmpty	The '{field}' field must not be an empty array.
arrayMin	The '{field}' field must contain at least {expected} items.
arrayMax	The '{field}' field must contain less than or equal to {expected} items.
arrayLength	The '{field}' field must contain {expected} items.
arrayContains	The '{field}' field must contain the '{expected}' item.
arrayUnique	The '{actual}' value in '{field}' field does not unique the '{expected}' values.
arrayEnum	The '{actual}' value in '{field}' field does not match any of the '{expected}' values.
tuple	The '{field}' field must be an array.
tupleEmpty	The '{field}' field must not be an empty array.
tupleLength	The '{field}' field must contain {expected} items.
boolean	The '{field}' field must be a boolean.
function	The '{field}' field must be a function.
date	The '{field}' field must be a Date.
dateMin	The '{field}' field must be greater than or equal to {expected}.
dateMax	The '{field}' field must be less than or equal to {expected}.
forbidden	The '{field}' field is forbidden.
‍‍email	The '{field}' field must be a valid e-mail.
emailEmpty	The '{field}' field must not be empty.
emailMin	The '{field}' field length must be greater than or equal to {expected} characters long.
emailMax	The '{field}' field length must be less than or equal to {expected} characters long.
url	The '{field}' field must be a valid URL.
enumValue	The '{field}' field value '{expected}' does not match any of the allowed values.
equalValue	The '{field}' field value must be equal to '{expected}'.
equalField	The '{field}' field value must be equal to '{expected}' field value.
object	The '{field}' must be an Object.
objectStrict	The object '{field}' contains forbidden keys: '{actual}'.
objectMinProps	"The object '{field}' must contain at least {expected} properties.
objectMaxProps	"The object '{field}' must contain {expected} properties at most.
uuid	The '{field}' field must be a valid UUID.
uuidVersion	The '{field}' field must be a valid UUID version provided.
mac	The '{field}' field must be a valid MAC address.
luhn	The '{field}' field must be a valid checksum luhn.

Message fields

Name	Description
field	The field name
expected	The expected value
actual	The actual value

Development

npm run dev

Test

npm test

Coverage report

-----------------|----------|----------|----------|----------|-------------------|
File             |  % Stmts | % Branch |  % Funcs |  % Lines | Uncovered Line #s |
-----------------|----------|----------|----------|----------|-------------------|
All files        |      100 |    97.73 |      100 |      100 |                   |
 lib             |      100 |      100 |      100 |      100 |                   |
  messages.js    |      100 |      100 |      100 |      100 |                   |
  validator.js   |      100 |      100 |      100 |      100 |                   |
 lib/helpers     |      100 |      100 |      100 |      100 |                   |
  deep-extend.js |      100 |      100 |      100 |      100 |                   |
  flatten.js     |      100 |      100 |      100 |      100 |                   |
 lib/rules       |      100 |    96.43 |      100 |      100 |                   |
  any.js         |      100 |      100 |      100 |      100 |                   |
  array.js       |      100 |      100 |      100 |      100 |                   |
  boolean.js     |      100 |      100 |      100 |      100 |                   |
  custom.js      |      100 |       50 |      100 |      100 |                 6 |
  date.js        |      100 |      100 |      100 |      100 |                   |
  email.js       |      100 |      100 |      100 |      100 |                   |
  enum.js        |      100 |       50 |      100 |      100 |                 6 |
  equal.js       |      100 |      100 |      100 |      100 |                   |
  forbidden.js   |      100 |      100 |      100 |      100 |                   |
  function.js    |      100 |      100 |      100 |      100 |                   |
  luhn.js        |      100 |      100 |      100 |      100 |                   |
  mac.js         |      100 |      100 |      100 |      100 |                   |
  multi.js       |      100 |      100 |      100 |      100 |                   |
  number.js      |      100 |      100 |      100 |      100 |                   |
  object.js      |      100 |      100 |      100 |      100 |                   |
  string.js      |      100 |    95.83 |      100 |      100 |             55,63 |
  tuple.js       |      100 |      100 |      100 |      100 |                   |
  url.js         |      100 |      100 |      100 |      100 |                   |
  uuid.js        |      100 |      100 |      100 |      100 |                   |
-----------------|----------|----------|----------|----------|-------------------|

Contribution

Please send pull requests improving the usage and fixing bugs, improving documentation and providing better examples, or providing some tests, because these things are important.

License

fastest-validator is available under the MIT license.

Contact

Copyright (C) 2019 Icebob

Changelog

1.13.0 (2022-08-15)

Changes

• update dev dependencies.
• update d.ts
• fixing string enum check in case of optional field. #284
• date rule add convert string to number for timestamp. #286
• fix(multi): item rule has custom checker will throw error if validate. #290
• fix backward compatibility issue. #298
• add new Record rule. #300

<a name="1.12.0"></a>