A progressive, client/server AB testing library.
Study is an AB testing library designed to be clear, minimal, and flexible. It works in both the server and browser with the use of driver-based persistence layers.
You can download the compiled javascript directly here
Features
- Powerful, clear API
- Many variations. ABCD testing
- Intelligent weighted bucketing
- Browser & Server support
- Storage Drivers:
localStorage
,cookies
,memory
, or build your own - Well documented, tested, and proven in high production environments
- Lightweight, weighing in at ~
3.8kb
. - Not tested on animals
Installing
# Via NPM npm i studyjs --save # Via Bower bower i studyjs --save # Via Yarn yarn add studyjs
Developing
npm install # Install dependencies npm build # Build the babel'd version npm lint # Run linting npm test # Run tests
Usage
API
Study(config)
const study = debug: true store: Studystoreslocal;
This creates a new test API used to defined tests, assign buckets, and retrieve information.
Returns: Object
Name | Type | Description | Default |
---|---|---|---|
debug |
Boolean |
Set to true to enable logging of additional information |
false |
store |
Object |
An object with get/set properties that will accept information to help persist and retrieve tests | Study.stores.local |
study.define(testData)
// Create your test APIconst study = ; // Define a teststudy;
This function defines the tests to be assigned to used during bucket assignment. This function accepts an object with two keys,
name
andbuckets
. Alternatively, you may pass an array of similar objects to define multiple tests at once.
The
name
value is the name of your test. The keys withinbucket
are your bucket names. Each bucket value is an object containing an object with an optional keyweight
that defaults to1
.
The percent chance a bucket is chosen for any given user is determined by the buckets weight divided by the total amount of all weights provided for an individual test. If you have three buckets with a weight of 2,
2/6 == 0.33
which means each bucket has a weight of33%
. There is no max for the total weights allowed.
Returns: null
Name | Type | Description | Default |
---|---|---|---|
data |
Object/Array |
An object/array of objects containing test and bucket information | null |
study.assign(testName, bucketName)
const study = ;study; // Assign buckets from all tests to the user...study; // or assign bucket from the specified test...study; // or specify the bucket from the specified test...study; // or remove the bucketing assignment from the specified test.study;
Calling the
assign
method will assign a bucket for the provided tests to a user and persist them to thestore
. If a user has already been bucketed, they will not be rebucketed unless abucketName
is explicitly provided.
If no arguments are provided, all tests will have a bucket assigned to the user. If the first argument provided is a test name, it will attempt to assign a bucket for that test to a user. If a
bucketValue
is provided, it will set that user to the specified bucket. If thebucketValue
is null, it will remove that users assignment to the bucket.
Returns: null
Name | Type | Description | Default |
---|---|---|---|
testName (optional) |
String |
The name of the test to assign a bucket to | null |
bucketName (optional) |
String |
The name of the bucket to assign to a user | null |
study.definitions()
const study = ;study; // Retrieve all of the provided testsconst tests = study;
This provides the user with all of the tests available.
The returned information will be an array if multiple tests were defined, otherwise, it will be an object of the single test defined. The object will mirror exactly what was provided in the
define
method.
Returns: Object|Array
study.assignments()
const study = ;study; // Capture assignmentsstudy; // Retrieve all of the bucket assignments for the userconst buckets = study;assert;
This provides the user with all of the bucket assignments for the current user.
The returned information will be an object whose keys will be test names and values will be the current bucket assigned to the user.
// Example return 'new-homepage': 'variantA' 'some-test': 'some-bucket'
Returns: Object|Array
study.extendAssignments
Extending assignments can be a useful way to augment your Study implementation with third party software.
const study = ; // Create a function that will modify assignments before you call `assignments`studyextendAssignments = Object // Retrieve all of the bucket assignments for the userconst buckets = study;assert;
A more practical example could be to implement with a third party AB testing platform like Optimizely (This uses pseudo code for brevity)
study { if windowoptimizely for const experiment in optimizely assignmentsexperimentname = experimentbucket return assignments}
Returns: Object
Guide/FAQ
CSS Driven Tests
Tests logic may be potentially powered on solely CSS. Upon calling assign
, if the script is running in the browser, a class per test will be added to the body
tag with the test name and bucket in BEM
syntax.
<!-- Could be new-homepage--variantB -->
Storing metadata associated with tests
Each bucket provided may have additional metadata associated with it, and may have its value retrieved by retrieving the assignments and definitions.
const study = ;study; study; const defs = study;const buckets = study;const bucket = buckets'new-homepage';const bar = defsbucketsbucketfoo; // "bar"
License
MIT Licensing
Copyright (c) 2015 - 2018 Dollar Shave Club
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.