Package Exports

validatex

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Readme

Introduction

A simple yet powerful data validator for javascript.

Installation

NPM

npm install validatex

Bower

bower install validatex

Quick walk through

import {validate, ValidationError, minLength, required, equalsTo} from "validatex";

// custom validator
let isUsername = (value) => {
    if (!/^[a-z0-9]{4,}$/.test(value)) {
        throw new ValidationError("Invalid username.");
    }
}

// define data schema
let signupSchema = {
    username: isUsername,
    password: [required(true), minLength(8)],
    confirmPassword: [required(true), equalsTo("password"), minLength(8)]
};


let data = {
    username: "123",
    password: "1234567",
    confirmPassword: "abcdefg"
};

// validate data against the schema
validate(data, signupSchema);
// =>
// { username: "Invalid username.",
//   password: "'password' must be at least 8 digits long.",
//   confirmPassword: "'confirmPassword' and 'password' do not match." }

// get multiple errors
validate(data, signupSchema, true);
// =>
// { username: [ "Invalid username." ],
//   password: [ "'password' must be at least 8 digits long." ],
//   confirmPassword: 
//    [ "'confirmPassword' and 'password' do not match.",
//      "'confirmPassword' must be at least 8 digits long." ] }

Syntax

validate(data, schema, multipleError?)

Validate single data

Single piece of data can be validated against single or multiple validators

With single validator

validate(1, isString());
// => '1' is not a valid string.

validate("apple", isString());
// => undefined

With multiple validators

validate("", [required(true), isNumber()]);
// => This field is required.

Get multiple errors

Pass true as the 3rd argument to the validate function to get multiple errors.

validate("", [required(true), isNumber()], true);
// => [ "This field is required.", "'' is not a valid number." ]

// returns empty list if data is valid
validate(1, [required(true), isNumber()], true);
// => []

Validate multiple data

Multiple data can be validated against single or multiple validators

let loginSchema = {
    username: required(true),
    password: [required(true), minLength(8)]
};

let loginData = {
    username: "ausername",
    password: ""
};

validate(loginData, loginSchema);
// => { username: undefined, password: 'This field is required.' }

Get multiple errors

Pass true as the 3rd argument to the validate function to get multiple errors.

validate(loginData, loginSchema, true);
// =>
// { username: [],
//   password: 
//    [ "This field is required.",
//      "'password' must be at least 8 digits long."] }

Customize error

Depending upon the validators custom error can be passed as an extra argument.

validate("", required(true, "This field cannot be blank."));
// => "This field cannot be blank."

// Error message can be templated to show the key and value.
let schema = {
    username: isString("Invalid value '{value}' for '{key}'.")
};

data = {
    username: 1
};

validate(data, schema);
// => { username: "Invalid value '1' for 'username'." }

Custom validator

A validator is a normal function which must throw error if data is invalid. It must return undefined if data is valid. Lets create a naive email validator.

let isEmail = (value) => {
    if (!/.+@.+\..+/.test(value)) {
        throw new ValidationError("Invalid email.");
    }
};

// invalid
validate("invalid@email", isEmail);
// => Invalid email.

// valid
validate("valid@email.com", isEmail);
// => undefined

Composing a validator

A validator can be composed to tune its behavior. Below is how minLength validator is composed.

// 'length' = length against which validation will be made
// 'error' = user suppoied error message which will override the default error message
let minLength = (length, error) => {
    // return actual validator
    return (value) => {
        if (value.length < length) {
            throw new ValidationError(error || `It must be at least ${length} characters long.`);
        }
    };
};

validate("1234", minLength(5));
// => It must be at least 5 characters long.

validate("1234", minLength(5, "Its too short."));
// => Its too short.

Short curcuit validation

A validator can return false to skip rest of the validation. This is how required validator works.

let required = (flag, error) => {
    return (value) => {
        if (flag && !value) {
            throw new ValidationError(error || "This field is required.");
        }
        else if (!flag && !value) {
            // skip rest of the validators
            return false;
        }
    }
};

// invalid
validate("", [required(false), isNumber]);
// => undefined

Validate against rest of the data

A validator gets entire data as 2nd argument so that one can validate against other data. Validator equalsTo makes use of this feature to ensure a data matches with another data.

let equalsTo = (key, error) => {
    // 'all' is entire data being validated
    return (value, all) => {
        if (value !== all[key]) {
            throw new ValidationError(error || `'{key}' and '${key}' do not match.`);
        }
    }
}; 

let schema = {
    password: required(true),
    confirmPassword: equalsTo("password")
};

let data = {
    password: "apassword",
    confirmPassword: "bpassword"
};

validate(data, schema);
// =>
// { password: undefined,
//   confirmPassword: "'confirmPassword' and 'password' do not match." }

Validators

Unlike validators in other libraries these validators must be used with the validate function.

isBoolean

Checks if a value is a boolean.

isBoolean(customError?)

isNumber

Checks if a value is a number.

isNumber(customError?)

isString

Checks if a value is a string.

isString(customError?)

isFunction

Checks if a value is a function.

isFunction(customError?)

isObject

Checks if a value is an object.

isObject(customError?)

isArray

Checks if a value is an array.

isArray(customError?)

isEmail

Checks if a value is an email.

isEmail()

required

Checks if a value exists.

required(true|false, customError?)

oneOf

Deprecated: use 'within' instead Checks if a value is one of the given items.

oneOf([...items], customError?)

noneOf

Deprecated: use 'excludes' instead Checks if a value is none of the given items.

noneOf([...items], customError?);

equalsTo

Makes sure if a value matches another value.

equalsTo(key, customError?)

length

Checks lenght of a value.

length(size, customError?)

minLength

Checks if a value's length is within the minimum length.

minLength(size, customError?)

maxLength

Checks if a value's length is within the maximum length.

maxLength(size, customError?)

within

Checks if a value or list of values fall under a given list.

within(list, customError?)

excludes

Checks if a value or list of values do not fall under a given list.

excludes(list, customError?)

pattern

Checks if a value is in the given pattern.

pattern(regex, customError?)