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The fastest JS validator library for NodeJS

Package Exports

  • fastest-validator

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (fastest-validator) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

Photos from @ikukevk

Node CI Coverage Status Codacy Badge Known Vulnerabilities Size

fastest-validator NPM version Tweet

⚡ 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:

Result

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

Table of contents

Installation

NPM

You can install it via NPM.

$ npm i fastest-validator --save

or

$ yarn add fastest-validator

Usage

Simple method

Call the validate method with the object and the schema.

If performance is important, you won't use this method because it's slow.

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
};

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

console.log(v.validate({ id: 5, name: "Al", status: true }, schema));
/* Returns an array with errors:
    [
        {
            type: 'stringMin',
            expected: 3,
            actual: 2,
            field: 'name',
            message: 'The \'name\' field length must be greater than or equal to 3 characters long!'
        }
    ]
*/

Try it on Repl.it

Fast method

In this case, 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>
var 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

import FastestValidator from "https://dev.jspm.io/fastest-validator";

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

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

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 }
}

v.validate({ name: "John", age: 42 }, schema); // Valid
v.validate({ name: "John" }, schema); // Valid
v.validate({ age: 42 }, schema); // 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 }
}

v.validate({ age: 42 }, schema); // Valid
v.validate({ age: null }, schema); // Valid
v.validate({ age: undefined }, schema); // Fail because undefined is disallowed
v.validate({}, schema); // Fail because undefined is disallowed

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
}

v.validate({ name: "John" }, schema); // Valid
v.validate({ name: "John", age: 42 }, schema); // 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" }
    ]
}

v.validate({ cache: true }, schema); // Valid
v.validate({ cache: "redis://" }, schema); // Valid
v.validate({ cache: 150 }, schema); // 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
};

v.validate("John", schema); // Valid
v.validate("Al", schema); // 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 obj = {}

v.validate(obj, schema); // 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: () => new Date()
    }
};

const obj = {}

v.validate(obj, schema); // 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
}

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.

var 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" }
}

v.validate({ prop: true }, schema); // Valid
v.validate({ prop: 100 }, schema); // Valid
v.validate({ prop: "John" }, schema); // Valid

array

This is an Array validator.

Simple example with strings:

const schema = {
    roles: { type: "array", items: "string" }
}

v.validate({ roles: ["user"] }, schema); // Valid
v.validate({ roles: [] }, schema); // Valid
v.validate({ roles: "user" }, schema); // Fail

Example with only positive numbers:

const schema = {
    list: { type: "array", min: 2, items: {
        type: "number", positive: true, integer: true
    } }
}

v.validate({ list: [2, 4] }, schema); // Valid
v.validate({ list: [1, 5, 8] }, schema); // Valid
v.validate({ list: [1] }, schema); // Fail (min 2 elements)
v.validate({ list: [1, -7] }, schema); // 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"
        }
    } }
}

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

Example for enum:

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

v.validate({ roles: ["user"] }, schema); // Valid
v.validate({ roles: ["user", "admin"] }, schema); // Valid
v.validate({ roles: ["guest"] }, schema); // Fail

Example for unique:

const schema = {
    roles: { type: "array", unique: true }
}

v.validate({ roles: ["user"] }, schema); // Valid
v.validate({ roles: [{role:"user"},{role:"admin"},{role:"user"}] }, schema); // Valid
v.validate({ roles: ["user", "admin", "user"] }, schema); // Fail
v.validate({ roles: [1, 2, 1] }, schema); // 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" }
}

v.validate({ status: true }, schema); // Valid
v.validate({ status: false }, schema); // Valid
v.validate({ status: 1 }, schema); // Fail
v.validate({ status: "true" }, schema); // 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:

v.validate({ status: "true" }, {
    status: { type: "boolean", convert: 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 }
}

v.validate({ rawData: Buffer.from([1, 2, 3]) }, schema); // Valid
v.validate({ rawData: 100 }, schema); // 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: '$' }
}

v.validate({ money_amount: '$12.99'}, schema); // Valid
v.validate({ money_amount: '$0.99'}, schema); // Valid
v.validate({ money_amount: '$12,345.99'}, schema); // Valid
v.validate({ money_amount: '$123,456.99'}, schema); // Valid

v.validate({ money_amount: '$1234,567.99'}, schema); // Fail
v.validate({ money_amount: '$1,23,456.99'}, schema); // Fail
v.validate({ money_amount: '$12,34.5.99' }, schema); // 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" }
}

v.validate({ dob: new Date() }, schema); // Valid
v.validate({ dob: new Date(1488876927958) }, schema); // Valid
v.validate({ dob: 1488876927958 }, schema); // 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:

v.validate({ dob: 1488876927958 }, {
    dob: { type: "date", convert: true}
}); // Valid

email

This is an e-mail address validator.

const schema = {
    email: { type: "email" }
}

v.validate({ email: "john.doe@gmail.com" }, schema); // Valid
v.validate({ email: "james.123.45@mail.co.uk" }, schema); // Valid
v.validate({ email: "abc@gmail" }, schema); // 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.

enum

This is an enum validator.

const schema = {
    sex: { type: "enum", values: ["male", "female"] }
}

v.validate({ sex: "male" }, schema); // Valid
v.validate({ sex: "female" }, schema); // Valid
v.validate({ sex: "other" }, schema); // 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 `===`
}

v.validate({ agreeTerms: true }, schema); // Valid
v.validate({ agreeTerms: false }, schema); // Fail

Example with other field:

const schema = {
    password: { type: "string", min: 6 },
    confirmPassword: { type: "equal", field: "password" }
}

v.validate({ password: "123456", confirmPassword: "123456" }, schema); // Valid
v.validate({ password: "123456", confirmPassword: "pass1234" }, schema); // 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" }
}

v.validate({ user: "John" }, schema); // Valid
v.validate({ user: "John", password: "pass1234" }, schema); // 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 obj = {
    user: "John",
    token: "123456"
}

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

function

This a Function type validator.

const schema = {
    show: { type: "function" }
}

v.validate({ show: function() {} }, schema); // Valid
v.validate({ show: Date.now }, schema); // Valid
v.validate({ show: "function" }, schema); // 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" }
}

v.validate({ cc: "452373989901198" }, schema); // Valid
v.validate({ cc: 452373989901198 }, schema); // Valid
v.validate({ cc: "4523-739-8990-1198" }, schema); // Valid
v.validate({ cc: "452373989901199" }, schema); // Fail

mac

This is an MAC addresses validator. 

const schema = {
    mac: { type: "mac" }
}

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

multi

This is a multiple definitions validator. 

const schema = {
    status: { type: "multi", rules: [
        { type: "boolean" },
        { type: "number" }
    ], default: true }
}

v.validate({ status: true }, schema); // Valid
v.validate({ status: false }, schema); // Valid
v.validate({ status: 1 }, schema); // Valid
v.validate({ status: 0 }, schema); // Valid
v.validate({ status: "yes" }, schema); // Fail

Shorthand multiple definitions:

const schema = {
    status: [
        "boolean",
        "number"
    ]
}

v.validate({ status: true }, schema); // Valid
v.validate({ status: false }, schema); // Valid
v.validate({ status: 1 }, schema); // Valid
v.validate({ status: 0 }, schema); // Valid
v.validate({ status: "yes" }, schema); // Fail

number

This is a Number validator.

const schema = {
    age: { type: "number" }
}

v.validate({ age: 123 }, schema); // Valid
v.validate({ age: 5.65 }, schema); // Valid
v.validate({ age: "100" }, schema); // 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
    } }
}

v.validate({
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345
    }
}, schema); // Valid

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

v.validate({
    address: {
        country: "Italy",
        city: "Rome",
        zip: 12345,
        state: "IT"
    }
}, schema); // 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. 
let 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"
    }
};

v.validate(obj, schema); // 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 }
    }
  }
}

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

v.validate(obj, schema); // Valid

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

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

string

This is a String validator.

const schema = {
    name: { type: "string" }
}

v.validate({ name: "John" }, schema); // Valid
v.validate({ name: "" }, schema); // Valid
v.validate({ name: 123 }, schema); // 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.
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 obj = {
    username: "   Icebob  "
};

v.validate(obj, schema); // 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" };

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

Example with items:

const schema = {
    grade: { type: "tuple", items: ["string", "number"] }
}

v.validate({ grade: ["David", 85] }, schema); // Valid
v.validate({ grade: [85, "David"] }, schema); // Fail (wrong position)
v.validate({ grade: ["Cami"] }, schema); // 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 }
        ] }
    ] }
}

v.validate({ location: ['New York', [40.7127281, -74.0060152]] }, schema); // Valid
v.validate({ location: ['New York', [50.0000000, -74.0060152]] }, schema); // Fail
v.validate({ location: ['New York', []] }, schema); // 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" }
}

v.validate({ url: "http://google.com" }, schema); // Valid
v.validate({ url: "https://github.com/icebob" }, schema); // Valid
v.validate({ url: "www.facebook.com" }, schema); // 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" }
}

v.validate({ uuid: "10ba038e-48da-487b-96e8-8d3b99b6d18a" }, schema); // Valid UUIDv4
v.validate({ uuid: "9a7b330a-a736-51e5-af7f-feaf819cdc9f" }, schema); // Valid UUIDv5
v.validate({ uuid: "10ba038e-48da-487b-96e8-8d3b99b6d18a", version: 5 }, schema); // Fail

Properties

Property Default Description
version 4 UUID version in range 1-6.

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" }
};

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

console.log(v.validate({ 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
        }
    }
};

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

console.log(v.validate({ 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(v.validate(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.startWith("+")) errors.push({ type: "phoneNumber" })
            return v.replace(/[^\d+]/g, ""); // Sanitize: remove all special chars except numbers
        }
    }	
};

console.log(v.validate({ name: "John", phone: "+36-70-123-4567" }, schema));
// Returns: true

console.log(v.validate({ name: "John", phone: "36-70-123-4567" }, schema));
/* 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.

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}"
    }
});

v.validate({ name: "John" }, { name: { type: "string", min: 6 }});
/* 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"
        }
    }
}
v.validate({ firstname: "John", lastname: 23 }, schema );
/* 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.
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.
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

@icebob @icebob