CRITICAL: Incorrect iOS free trial period mapping - shows "1 day" instead of "14 days" after v14 migration

[ArekChr]

Bug Description

After migrating from react-native-iap versions 12/13 to version 14, the iOS subscription free trial period mapping is incorrect. A 14-day (2-week) free trial is being mapped as:

• introductoryPriceNumberOfPeriodsIOS: "1"
• introductoryPriceSubscriptionPeriodIOS: "day"

Instead of the expected:

• introductoryPriceNumberOfPeriodsIOS: "2"
• introductoryPriceSubscriptionPeriodIOS: "week"

Environment

• react-native-iap version: 14.4.23 (migrated from v12/13)
• Platform: iOS
• React Native version: 0.81.4
• Target iOS versions: iOS 15+ (StoreKit 2)

Expected vs Actual Behavior

Expected for 14-day free trial:

{
  "introductoryPriceNumberOfPeriodsIOS": "2",
  "introductoryPriceSubscriptionPeriodIOS": "week"
}

Actual (after migration):

{
  "introductoryPriceNumberOfPeriodsIOS": "1",
  "introductoryPriceSubscriptionPeriodIOS": "day"
}

Evidence from StoreKit Raw Data
The jsonRepresentationIOS field shows the correct Storekit 2 data:

jsonRepresentationIOS

{"attributes":{"description":{"standard":"Pro"},"editorialArtwork":{},"icuLocale":"pl_PL@currency=PLN","isFamilyShareable":0,"isMerchandisedEnabled":0,"isMerchandisedVisibleByDefault":0,"isSubscription":1,"kind":"Auto-Renewable Subscription","name":"SmartWorkout Pro","offerName":"com.arkadiuszchr.SmartWorkout.pro.yearly","offers":[{"assets":[],"buyParams":"productType=A&price=159990&salableAdamId=1578674504&pricingParameters=STDQ&pg=bruno_pln&offerName=com.arkadiuszchr.SmartWorkout.pro.yearly&appAdamId=1510802814","currencyCode":"PLN","discounts":[{"modeType":"FreeTrial","numOfPeriods":1,"price":0,"priceFormatted":"0,00 zł","priceString":"0","recurringSubscriptionPeriod":"P14D","type":"IntroOffer"}],"price":159.99000000000001,"priceFormatted":"159,99 zł","priceString":"159.99","recurringSubscriptionPeriod":"P1Y","type":"buy"}],"releaseDate":"2009-06-17","subscriptionFamilyId":"20857400","subscriptionFamilyName":"Subskrypcja","subscriptionFamilyRank":8,"supportsRuntimePricing":0,"url":"https:\/\/sandbox.itunes.apple.com\/pl\/app\/smartworkout-pro\/id1510802814?l=pl"},"href":"\/v1\/catalog\/pl\/in-apps\/1578674504?l=pl","id":"1578674504","type":"in-apps"}

{
  "discounts": [{
    "modeType": "FreeTrial",
    "numOfPeriods": 1,
    "price": 0,
    "priceFormatted": "0,00 zł",
    "priceString": "0",
    "recurringSubscriptionPeriod": "P14D",
    "type": "IntroOffer"
  }]
}

[hyochan]

Problem

A 14-day free trial was incorrectly mapped as:

{
  "introductoryPriceNumberOfPeriodsIOS": "1",
  "introductoryPriceSubscriptionPeriodIOS": "day"
}

Instead of the expected:

{
  "introductoryPriceNumberOfPeriodsIOS": "2",
  "introductoryPriceSubscriptionPeriodIOS": "week"
}

Root Cause

StoreKit 2 represents periods with both value and unit. A 14-day trial is represented as:

• period.value = 14
• period.unit = .day

However, OpenIAP was using only the unit directly without normalizing the period to its largest possible unit.

Fix

Added normalizePeriod() function that converts periods to their most human-readable format, and properly handles periodCount for pay-as-you-go offers:

Supported Conversions:

From Days

• 7 days → 1 week
• 14 days → 2 weeks ⭐
• 21 days → 3 weeks
• 365 days → 1 year

From Weeks

• 52 weeks → 1 year

From Months

• 12 months → 1 year
• 24 months → 2 years

Note: Month conversions from days/weeks are intentionally avoided because calendar months have variable lengths (28-31 days), which could lead to incorrect period representations.

Examples

Free Trial (periodCount = 1):

• 14 days → 2 weeks × 1 = 2 weeks total

Pay-as-you-go (periodCount > 1):

• $0.99/month for 3 months → 1 month × 3 = 3 months total ✅
• Previously would have incorrectly shown as "1 month"

Result: Both free trials and pay-as-you-go offers now show correct total periods ✅

[ArekChr]

Thank you for the fix 🙏 that was quick!