> 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:
*`!`: 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
<details>
<summary><strong>Contributing</strong></summary>
Pull requests and stars are always welcome. For bugs and feature requests, [please create an issue](../../issues/new).
</details>
<details>
<summary><strong>Running Tests</strong></summary>
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
```
</details>
<details>
<summary><strong>Building docs</strong></summary>
_(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:
* [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.")
