Anything ¯\_(ツ)_/¯

This module allows you to generate completely random variables, which is sometimes useful in testing. There are situations when you want to write a little property-based test, but you don't want to use a full framework for that.

That's where Anything comes in.

Anything is a tiny, zero-dependency utility for generating random stuff.

Anything in a nutshell

Installation

Install it with yarn:

yarn add -D any-thing

Or, if you use npm:

npm install --save-dev any-thing

Usage

An example of usage with Jest:

import _ from 'lodash'
import { anything } from 'any-thing'

test('makeOkResponse', () => {
  /* a tiny property-based test */
  _.times(100, () => {
    const thing = anything()
    expect(makeOkResponse(thing)).toEqual({ status: "OK", payload: thing })
  })
})

Anything includes 9 generators, which produce, respectively:

• Arrays
• Booleans
• Functions
• Integers
• Numbers (floats)
• Objects
• Strings
• null
• undefined

Arrays, functions and objects may also be nested.

API

anything(options = {})

Generates anything. You may provide options for each generator. Options is an object that contains options for all (or some) generators. The overall shape is:

{
  array: { /* array options */ },
  boolean: { /* boolean options */ },
  function: { /* function options */ },
  integer: { /* integer options */ },
  /* and so on for other generators */
}

See also: Generator options.

anything.but(generators..., options = {})

Generates anything, but does not use specified generators. For example, anything.but(Array, Object) will generate anything but an array or an object.

anything.except(generators..., options = {})

Alias for anything.but.

anything.from(generators..., options = {})

Generates anything using a whitelist of generators. For example, anything.from(null, undefined) will return either null or undefined.

Specific generators

There's also a function for each generator:

• anyArray()
• anyBoolean()
• anyFunction()
• anyInteger()
• anyNumber()
• anyObject()
• anyString()

These functions accept options, which are specific for each generator.

Generator options

Array

• minLength: minimum length of the array. Default: 0
• maxLength: maximum length of the array. Default: 10
• maxDepth: maximum depth ("nestedness") of the array. Default: 3

Example:

anyArray({ minLength: 1, maxLength: 2, maxDepth: 2 })
// => [ -923712 ]

Boolean

This generator doesn't have any options.

Example:

anyBoolean()
// => true

Function

• maxDepth: maximum depth of the function. Default: 3

Example:

anyFunction({ maxDepth: 2 })
// => function () { return 23123 }

Integer

• min: minimum value. Default: -1,000,000
• max: maximum value. Default: 1,000,000

Example:

anyInteger({ min: 0, max: 42 })
// => 42
// i knew I'd get 42
// what else could it be

Number (float)

• min: minimum value. Default: -1,000,000
• max: maximum value. Default: 1,000,000

Example:

anyNumber({ min: 0, max: 42 })
// => 30.172931281536908

String

• minLength: minimum length. Default: 0
• maxLength: maximum length. Default: 10
• alphabet: characters to use when generating a stirng. May be a string or an array. Default: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789

Example:

anyString({ minLength: 10, maxLength: 30, alphabet: '(!*@#!@ )' })
// => '! @ !#*(!*@)('

Object

• minLength: minimum object length (number of entries). Default: 0
• maxLength: maximum object length. Default: 10
• maxDepth: maximum object depth. Default: 3
• minStringLength: minimum length of keys. Default: 1
• maxStringLength: maximum length of keys. Default: 20
• alphabet: alphabet to use when generating keys. Defaults to String generator's default

Example:

anyObject({
  minLength: 0,
  maxLength: 2,
  maxDepth: 1,
  minStringLength: 1,
  maxStringLength: 4,
  alphabet: '!@#$%^'
})
// => {}
// of course that's what I get
// rng often seems like it's not random at all