🍞 Breadknife.js 🍞

Dead Simple A/B Testing so you can focus on getting that bread 🍞.

Install

npm install breadknife or yarn add breadknife

Usage

Setting up a test

First import the library. import Breadknife from 'breadknife'

Second you need a config file to list out the A/B tests you are using, the format is an array of objects, this can be anywhere in your code or even come from a database if need be.

const  exampleConfig  = [
	{
		id:  'EXAMPLE_TEST',
		split:  {
			TEST: 0.5,
			CONTROL: 0.5
		},
	}
]

Once your config is set you have to initialize the tests. Breadknife.init(exampleConfig)

Then you can check the slice of a test anywhere else in your code. Breadknife.getSlice('EXAMPLE_TEST') this will return a string matching one of the constants in Breadknife.states 'CONTROL' 'TEST' 'TEST_B' 'TEST_C'

you can use this to conditionally render code:

	let text
	if(Breadknife.getSlice('EXAMPLE_TEST') === Breadknife.TEST){
		text = "I'm test text!"
	} else {
		text = "I'm control text!"
	}

Disabling a test

Breadknife stores all tests on the clients local storage so that slices can persist between sessions, if you need to temporarily disable a test without removing it you can add disabled: true to the config for that test. Disabled tests always return Breadknife.CONTROL

const  exampleConfig  = [
	{
		id:  'EXAMPLE_TEST',
		split:  {
			TEST: 0.5,
			CONTROL: 0.5
		},
		disabled: true
	}
]

Removing a test

If a test is not longer necessary it can simply be removed from the config and it wont be saved on the next Breadknife.init() call, if a test that does not exist is provided to the Breadknife.getSlice() function, it will always return Breadknife.CONTROL

Config

id

The id of a test must be a unique string, duplicate ID's in the same config result in an error.

The split object

The split object must be a an object with at least a TEST and CONTROL parameter, you can have up to a 4 way split test by adding a TEST_B and TEST_C to the object.

Finally, all of the values in the split object must be floats that when added together equal between 0.99 and 1 (not just 1 because 3 way tests can sometimes result in imperfect math)

Three way test:

exampleConfig  = [
	{
		id:  'EXAMPLE_TEST',
		split:  {
			CONTROL:  0.33,
			TEST:  0.33,
			TEST_B:  0.33,
		},
	}
]

Four way test:

exampleConfig  = [
	{
		id:  'EXAMPLE_TEST',
		split:  {
			CONTROL:  0.25,
			TEST:  0.25,
			TEST_B:  0.25,
			TEST_C:  0.25,
		},
	}
]

Constants for easier test definition

Breadknife comes with 3 predefined constants HALF_AND_HALF, THREE_WAY and FOUR_WAY for when you just want a dead simple split for your tests.

import Breadknife, { HALF_AND_HALF } from 'breadknife'
const  exampleConfig  = [
	{
		id:  'EXAMPLE_TEST',
		split:  HALF_AND_HALF
	},
	{
		id:  'EXAMPLE_3_WAY',
		split:  THREE_WAY
	},
	{
		id:  'EXAMPLE_4_WAY',
		split:  FOUR_WAY
	}
]

Forcing a test version

If you need to force a test into a certain slice you can use the Breadknife.forceTestSlice(id, state) function.

Listing all tests

If you need to return a list of all tests with their slices you can use Breadknife.getTests()