ab-test-result - npm Package Compare versions

Comparing version 1.0.5 to 1.1.0

index.js

@@ -19,4 +19,10 @@ const BigNumber = require('bignumber.js');
 	const B_rate = calcConversionRate(B_visits, B_conversions);
-	const B_improvement = B_rate.sub(A_rate).div(A_rate);
 
+	let B_improvement;
+	if (A_rate.isZero() || B_rate.isZero()) {
+		B_improvement = new BigNumber(0);
+	} else {
+		B_improvement = B_rate.sub(A_rate).div(A_rate);
+	}
+
 	const A_stdErr = calcStandardError(A_visits, A_conversions);
@@ -44,2 +50,5 @@ const B_stdErr = calcStandardError(B_visits, B_conversions);
 function calcConversionRate(visits, conversions) {
+	if (conversions.isZero()) {
+		return new BigNumber(0);
+	}
 	return conversions.div(visits);
@@ -49,2 +58,5 @@ }
 function calcStandardError(visits, conversions) {
+	if (visits.isZero()) {
+		return new BigNumber(0);
+	}
 	const rate = calcConversionRate(visits, conversions);
@@ -58,2 +70,5 @@ const dividend = rate.mul( new BigNumber(1).sub(rate) );
 	const stdErrOfDiff = A_stdErr.pow(2).add(B_stdErr.pow(2)).sqrt();
+	if (stdErrOfDiff.isZero()) {
+		return new BigNumber(0);
+	}
 	return (rateDiff).div(stdErrOfDiff);
@@ -60,0 +75,0 @@ }

package.json

 {
   "name": "ab-test-result",
-  "version": "1.0.5",
+  "version": "1.1.0",
   "description": "Returns the improvement rate of your AB-test and answers if it's statistically significant",
@@ -5,0 +5,0 @@ "main": "index.js",

test/calculations.spec.js

@@ -5,2 +5,90 @@ const abTestResult = require('..');
 
+	describe('when some values are zero', () => {
+
+		describe('when all values are zero', () => {
+			var result;
+
+			before(() => {
+				result = abTestResult.calcResult({
+					controlVisits: 0,
+					controlConversions: 0,
+					challengerVisits: 0,
+					challengerConversions: 0
+				});
+			});
+
+			it('should return result without any NaN values', () => {
+				expect(result).to.eql({
+					controlConversionRate: 0,
+					challengerConversionRate: 0,
+					challengerImprovement: 0,
+					isSignificant: false,
+					statistics: {
+						controlStandardError: 0,
+						challengerStandardError: 0,
+						zScore: 0,
+						pValue: 0.5
+					}
+				});
+			});
+		});
+
+		describe('when controlConversions is zero', () => {
+			var result;
+
+			before(() => {
+				result = abTestResult.calcResult({
+					controlVisits: 0,
+					controlConversions: 0,
+					challengerVisits: 10,
+					challengerConversions: 5
+				});
+			});
+
+			it('should return result without any NaN values', () => {
+				expect(result).to.eql({
+					controlConversionRate: 0,
+					challengerConversionRate: 0.5,
+					challengerImprovement: 0,
+					isSignificant: true,
+					statistics: {
+						controlStandardError: 0,
+						challengerStandardError: 0.15811388300841897,
+						zScore: 3.1622776601683795,
+						pValue: 0.0010000000000000009
+					}
+				});
+			});
+		});
+
+		describe('when challengerConversions is zero', () => {
+			var result;
+
+			before(() => {
+				result = abTestResult.calcResult({
+					controlVisits: 10,
+					controlConversions: 5,
+					challengerVisits: 0,
+					challengerConversions: 0
+				});
+			});
+
+			it('should return result without any NaN values', () => {
+				expect(result).to.eql({
+					controlConversionRate: 0.5,
+					challengerConversionRate: 0,
+					challengerImprovement: 0,
+					isSignificant: true,
+					statistics: {
+						controlStandardError: 0.15811388300841897,
+						challengerStandardError: 0,
+						zScore: -3.1622776601683795,
+						pValue: 0.999
+					}
+				});
+			});
+		});
+
+	});
+
 	describe('when challenger performs better than or equal to control', () => {
@@ -7,0 +95,0 @@ describe('when no min confidense is provided', () => {

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Improved metrics

Total package byte prevSize

19590

increased by12.72%

Lines of code

597

increased by17.98%

Worsened metrics

Number of package files

11

decreased by-8.33%

No dependency changes