Overview

A simple way to check that password strength of a certain passphrase. A password strength checker based from Javascript RegEx.

DEMO 1 by @Ennoriel

DEMO 2

Installation

Install via Package Manager

npm i check-password-strength --save

Install via Browser Script Tag using UNPKG

<script src="https://unpkg.com/check-password-strength/dist/umd.js"></script>

Setup & Basic Usage

const { passwordStrength } = require('check-password-strength')
// OR
import { passwordStrength } from 'check-password-strength'

console.log(passwordStrength('asdfasdf').value)
// Too weak (It will return Too weak if the value doesn't match the RegEx conditions)

console.log(passwordStrength('asdf1234').value)
// Weak

console.log(passwordStrength('Asd1234!').value)
// Medium

console.log(passwordStrength('A@2asdF2020!!*').value)
// Strong

Migration from 1.x.x to 2.0.0

// 1.x.x
const whateEverYourFunctionNameWasBefore = require("./index");

// 'contains' attribute of the response object format was
response.contains = [{'message': 'lowercase'}, ...]

// 2.0.0
const { passwordStrength : whateEverYourFunctionNameWasBefore } = require("./index");

// 'contains' attribute of the response object format is now
response.contains = ['lowercase', ...]

Additional Info

Object Result

Property	Desc.
id	0 = Too weak, 1 = Weak & 2 = Medium, 3 = Strong
value	Too weak, Weak, Medium & Strong
contains	lowercase, uppercase, symbol and/or number
length	length of the password

Password Length Default Options

Name	Mininum Diversity	Mininum Length
Too weak	0	0
Weak	2	6
Medium	4	8
Strong	4	10

console.log(passwordStrength('@Sdfasd2020!@#$'))
// output 
{ 
    "id": 1, 
    "value": "Strong",
    "contains": ['lowercase', 'uppercase', 'symbol', 'number'],
    "length": 15
}

Default Options

The default symbols are based from Password Special Characters OWASP list (except for the space)

!"#$%&'()*+,-./:;<=>?@[\]^_`{|}~

Thanks for jlherren & Ennoriel for this suggestion! 👨🏻‍💻👨🏻‍💻

The default options can be required:

const { defaultOptions } = require("./index");

default options:

[
  {
    id: 0,
    value: "Too weak",
    minDiversity: 0,
    minLength: 0
  },
  {
    id: 1,
    value: "Weak",
    minDiversity: 2,
    minLength: 6
  },
  {
    id: 2,
    value: "Medium",
    minDiversity: 4,
    minLength: 8
  },
  {
    id: 3,
    value: "Strong",
    minDiversity: 4,
    minLength: 10
  }
]

To override the default options, simply pass your custom array as the second argument:

id: correspond to the return id attribute.
value: correspond to the return value attribute.
minDiversity: between 0 and 4, correspond to the minimum of different criterias ('lowercase', 'uppercase', 'symbol', 'number') that should be met to pass the password strength
minLength: minimum length of the password that should be met to pass the password strength

The minDiversity and minLength parameters of the first element cannot be overriden (set to 0 at the beginning of the method). Therefore, the first element should always correspond to a "too weak" option.

passwordStrength('myPassword', yourCustomOptions)

RegEx

Strong

 ^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%^&*"'()+,-./:;<=>?[\]^_`{|}~])(?=.{10,})

Medium Password RegEx used:

 ^(?=.*[a-z])(?=.*[A-Z])(?=.*[0-9])(?=.*[!@#$%^&*"'()+,-./:;<=>?[\]^_`{|}~])(?=.{8,})

RegEx	Desc.
^	The password string will start this way
(?=.*[a-z])	The string must contain at least 1 lowercase alphabetical character
(?=.*[A-Z])	The string must contain at least 1 uppercase alphabetical character
(?=.*[0-9])	The string must contain at least 1 numeric character
(?=.[!"#$%&'()*+,-./:;<=>?@[\]^_`{\|}~]))	The string must contain at least one special character
(?=.{10,})	The string must be eight characters or longer for Strong strength
(?=.{8,})	The string must be eight characters or longer for Medium strength
(?=.{6,})	Mininum of 6 characters for Weak strength

TypeScript type declarations ☑

Available starting version v2.0.3 and above. (Thanks to @Mesoptier!)

Other resources

For .NET Project

If you're working with .net core project, I've created a simple nuget package with same RegEx strings to validate a password strength.

You can easily install via Nuget Package Manager or .NET CLI (Check.Password.Strength). This package uses Regular Expression new Regex() derives from System.Text.RegularExpressions. You can use this especially if you want to validate the passcode strength on backend services or web apis of your project.

Other NPM RegEx validator

I also made another NPM package (hey-regex) that checks common inputs like numbers (whole number and decimal), alpha numeric, email and url. This package only returns true or false based from the selected function (with RegEx .test() inside).

Reference blog.

Contribute

Feel free to clone or fork this project: https://github.com/deanilvincent/check-password-strength.git

Contributions & pull requests are welcome!

I'll be glad if you give this project a ★ on Github :)

Kudos to @Ennoriel and his efforts for making v2.x.x possible!

License

This project is licensed under the MIT License - see the LICENSE.md file for details.

dyh333/check-password-strength