SplitTesting.js

This library allows you to easily implement split testing to your website, it's fully written in TypeScript with a functional programming and declarative paradigm in mind.

Features :

• Variant saved in localStorage
• Multiple variants (A/B, A/B/C, etc...)
• Weighted variants for defining the chance of being picked
• Seed option for cross-device consistency (ex: userID as a seed)

Installation

SplitTesting.js is available on npm and can be installed by running:

npm install split-testing

Basic Usage

This is how you would use SplitTesting.js in ES6 to create an experiment:

import { setExperiment, getPickedVariant } from 'split-testing';

// Configuration of the experiment 
const experimentName = 'abtest-basic'
const variants = [
  { name: 'control', data: {} },
  { name: 'test', data: {} }
]

// Setting up the experiment
setExperiment({
  name: experimentName,
  variants,
  onVariantPicked: (pickedVariant) => {
    // When the variant is first picked for the user (= first-load of the page)
    console.log(`Variant picked, named "${pickedVariant.name}"`)
  }
})

If no variant is detected in localStorage, one will be randomly picked (same chance for all the variants), which will trigger the onVariantPicked method if provided.

The code is synchrone, so after the execution of setExperiment you can directly access the persistant variant like so :

const pickedVariant = getPickedVariant({ experimentName, variants })

The name of the experiment is used in the property name of the localStorage, that's why we need to pass it in the different methods for getting the saved variant.

Advance Usage

1) Seeded variant

For more persistance, you can add a seed property, it will have for effect to always return the same variant.

SplitTesting.setExperiment({
  name: 'abtest-seed',
  variants: [
    { name: 'control' },
    { name: 'test' } // ALWAYS PICKED
  ],
  seed: 'a constant string'
})

For example, by putting the userID as the seed: the variant will be persitent whatever the device used by the user.

2) Weighted variant

By default all variants have the same probability of being picked at first load, but you can change that with the weight property :

SplitTesting.setExperiment({
  name: 'abtest-weighted',
  variants: [
    { name: 'control', weight: 0.50 }, // 50% chance
    { name: 'test1', weight: 0.25 }, // 25% chance
    { name: 'test2', weight: 0.25 } // 25% chance
  ]
})

Warning - The weight values will be reseted to the default ones if :

• The total of all weight is not equal to 1
• Some variants have a weight property and others no

In those cases, a warning will be present in the console.

Debug mode

The debug mode will log various messages of information into the console, allowing you to better understand what the library is doing.

To activate it, simply add debug: true to the experiment options :

SplitTesting.setExperiment({
  name: experimentName,
  variants,
  debug: true
})

CDN source

If you don't use NodeJS at all, you can add SplitTesting.js to your website using this line in your HTML :

<script defer src="https://unpkg.com/split-testing@0.3.0/dist/bundle.js"></script>
<!-- Check and take the latest version -->

You will then have a global variable SplitTesting available, containing all the methods you need.

Todo

• Having 0 dependency
• Option for allowing or not the seed conflict check
• Adding a test library for validating the methods and the randomness