# randomatic [](https://www.npmjs.com/package/randomatic) [](https://npmjs.org/package/randomatic) [](https://npmjs.org/package/randomatic) [](https://travis-ci.org/jonschlinkert/randomatic)
> Generate randomized strings of a specified length using simple character sequences. The original generate-password.
Please consider following this project's author, [Jon Schlinkert](https://github.com/jonschlinkert), and consider starring the project to show your :heart: and support.
## Install
Install with [npm](https://www.npmjs.com/):
```sh
$ npm install --save randomatic
```
## Usage
```js
var randomize = require('randomatic');
```
## API
```js
randomize(pattern, length, options);
randomize.isCrypto;
```
* `pattern` **{String}**: (required) The pattern to use for randomizing
* `length` **{Number}**: (optional) The length of the string to generate
* `options` **{Object}**: (optional) See available [options](#options)
* `randomize.isCrypto` will be `true` when a cryptographically secure function is being used to generate random numbers. The value will be `false` when the function in use is `Math.random`.
### pattern
> The pattern to use for randomizing
Patterns can contain any combination of the below characters, specified in any order.
**Example:**
To generate a 10-character randomized string using all available characters:
```js
randomize('*', 10);
//=> 'x2_^-5_T[$'
randomize('Aa0!', 10);
//=> 'LV3u~BSGhw'
```
* `a`: Lowercase alpha characters (`abcdefghijklmnopqrstuvwxyz'`)
* `A`: Uppercase alpha characters (`ABCDEFGHIJKLMNOPQRSTUVWXYZ'`)
* `0`: Numeric characters (`0123456789'`)
* `!`: Special characters (`~!@#$%^&()_+-={}[];\',.`)
* `*`: All characters (all of the above combined)
* `?`: Custom characters (pass a string of custom characters to the options)
### length
> The length of the string to generate
**Examples:**
* `randomize('A', 5)` will generate a 5-character, uppercase, alphabetical, randomized string, e.g. `KDJWJ`.
* `randomize('0', 2)` will generate a 2-digit random number
* `randomize('0', 3)` will generate a 3-digit random number
* `randomize('0', 12)` will generate a 12-digit random number
* `randomize('A0', 16)` will generate a 16-character, alpha-numeric randomized string
If `length` is left undefined, the length of the pattern in the first parameter will be used. For example:
* `randomize('00')` will generate a 2-digit random number
* `randomize('000')` will generate a 3-digit random number
* `randomize('0000')` will generate a 4-digit random number...
* `randomize('AAAAA')` will generate a 5-character, uppercase alphabetical random string...
These are just examples, [see the tests](./test.js) for more use cases and examples.
## options
> These are options that can be passed as the third argument.
#### chars
Type: `String`
Default: `undefined`
Define a custom string to be randomized.
**Example:**
* `randomize('?', 20, {chars: 'jonschlinkert'})` will generate a 20-character randomized string from the letters contained in `jonschlinkert`.
* `randomize('?', {chars: 'jonschlinkert'})` will generate a 13-character randomized string from the letters contained in `jonschlinkert`.
#### exclude
Type: `String|Array`
Default: `undefined`
Specify a string or array of characters can are excluded from the possible characters used to generate the randomized string.
**Example:**
* `randomize('*', 20, { exclude: '0oOiIlL1' })` will generate a 20-character randomized string using all of possible characters except for `0oOiIlL1`.
## Usage Examples
* `randomize('A', 4)` (_whitespace insenstive_) would result in randomized 4-digit uppercase letters, like, `ZAKH`, `UJSL`... etc.
* `randomize('AAAA')` is equivelant to `randomize('A', 4)`
* `randomize('AAA0')` and `randomize('AA00')` and `randomize('A0A0')` are equivelant to `randomize('A0', 4)`
* `randomize('aa')`: results in double-digit, randomized, lower-case letters (`abcdefghijklmnopqrstuvwxyz`)
* `randomize('AAA')`: results in triple-digit, randomized, upper-case letters (`ABCDEFGHIJKLMNOPQRSTUVWXYZ`)
* `randomize('0', 6)`: results in six-digit, randomized numbers (`0123456789`)
* `randomize('!', 5)`: results in single-digit randomized, _valid_ non-letter characters (`~!@#$%^&()_+-={}[]
* `randomize('A!a0', 9)`: results in nine-digit, randomized characters (any of the above)
_The order in which the characters are defined is insignificant._
## About
Contributing
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
Running Tests
Running and reviewing unit tests is a great way to get familiarized with a library and its API. You can install dependencies and run tests with the following command:
```sh
$ npm install && npm test
```
Building docs
_(This project's readme.md is generated by [verb](https://github.com/verbose/verb-generate-readme), please don't edit the readme directly. Any changes to the readme must be made in the [.verb.md](.verb.md) readme template.)_
To generate the readme, run the following command:
```sh
$ npm install -g verbose/verb#dev verb-generate-readme && verb
```
### Related projects
You might also be interested in these projects:
* [pad-left](https://www.npmjs.com/package/pad-left): Left pad a string with zeros or a specified string. Fastest implementation. | [homepage](https://github.com/jonschlinkert/pad-left "Left pad a string with zeros or a specified string. Fastest implementation.")
* [pad-right](https://www.npmjs.com/package/pad-right): Right pad a string with zeros or a specified string. Fastest implementation. | [homepage](https://github.com/jonschlinkert/pad-right "Right pad a string with zeros or a specified string. Fastest implementation.")
* [repeat-string](https://www.npmjs.com/package/repeat-string): Repeat the given string n times. Fastest implementation for repeating a string. | [homepage](https://github.com/jonschlinkert/repeat-string "Repeat the given string n times. Fastest implementation for repeating a string.")
### Contributors
| **Commits** | **Contributor** |
| --- | --- |
| 56 | [jonschlinkert](https://github.com/jonschlinkert) |
| 6 | [doowb](https://github.com/doowb) |
| 4 | [kivlor](https://github.com/kivlor) |
| 2 | [realityking](https://github.com/realityking) |
| 2 | [ywpark1](https://github.com/ywpark1) |
| 1 | [TrySound](https://github.com/TrySound) |
| 1 | [drag0s](https://github.com/drag0s) |
| 1 | [paulmillr](https://github.com/paulmillr) |
| 1 | [sunknudsen](https://github.com/sunknudsen) |
| 1 | [faizulhaque-tp](https://github.com/faizulhaque-tp) |
| 1 | [michaelrhodes](https://github.com/michaelrhodes) |
### Author
**Jon Schlinkert**
* [GitHub Profile](https://github.com/jonschlinkert)
* [Twitter Profile](https://twitter.com/jonschlinkert)
* [LinkedIn Profile](https://linkedin.com/in/jonschlinkert)
### License
Copyright © 2018, [Jon Schlinkert](https://github.com/jonschlinkert).
Released under the [MIT License](LICENSE).
***
_This file was generated by [verb-generate-readme](https://github.com/verbose/verb-generate-readme), v0.8.0, on October 23, 2018._