78 lines
2.3 KiB
JavaScript
78 lines
2.3 KiB
JavaScript
/*
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* Bucketing wrapper for creating AB-tests.
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*
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* Given a test name, sampling rate, and session ID, provides a class that buckets a user into
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* a predefined bucket ("unsampled", "control", or "treatment") and starts an AB-test.
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*/
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( function ( M, mwExperiments ) {
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var bucket = {
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UNSAMPLED: 'unsampled', // Old treatment: not sampled and not instrumented.
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CONTROL: 'control', // Old treatment: sampled and instrumented.
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TREATMENT: 'treatment' // New treatment: sampled and instrumented.
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};
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/**
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* Buckets users based on params and exposes an `isSampled` and `getBucket` method.
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* @param {Object} config Configuration object for AB test.
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* @param {string} config.testName
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* @param {number} config.samplingRate Sampling rate for the AB-test.
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* @param {number} config.sessionId Session ID for user bucketing.
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* @constructor
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*/
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function AB( config ) {
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var
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testName = config.testName,
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samplingRate = config.samplingRate,
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sessionId = config.sessionId,
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test = {
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name: testName,
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enabled: !!samplingRate,
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buckets: {
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unsampled: 1 - samplingRate,
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control: samplingRate / 2,
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treatment: samplingRate / 2
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}
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};
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/**
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* Gets the users AB-test bucket.
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*
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* A boolean instead of an enum is usually a code smell. However, the nature of A/B testing
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* is to compare an A group's performance to a B group's so a boolean seems natural, even
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* in the long term, and preferable to showing bucketing encoding ("unsampled", "control",
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* "treatment") to callers which is necessary if getBucket(). The downside is that now two
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* functions exist where one would suffice.
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*
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* @return {string} AB-test bucket, `bucket.UNSAMPLED` by default, `bucket.CONTROL` or
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* `bucket.TREATMENT` buckets otherwise.
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*/
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function getBucket() {
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return mwExperiments.getBucket( test, sessionId );
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}
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function isControl() {
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return getBucket() === bucket.CONTROL;
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}
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function isTreatment() {
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return getBucket() === bucket.TREATMENT;
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}
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/**
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* Checks whether or not a user is in the AB-test,
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* @return {boolean}
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*/
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function isSampled() {
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return getBucket() !== bucket.UNSAMPLED; // I.e., `isControl() || isTreatment()`
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}
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return {
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isControl: isControl,
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isTreatment: isTreatment,
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isSampled: isSampled
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};
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}
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module.exports = AB;
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}( mw.mobileFrontend, mw.experiments ) );
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