Buy purchase option without discount on oneTimePurchaseOfferDetailsAndroid does not have an offer ID

[simmotde]

My team is setting up different purchase options for a one time in-app purchase. Each purchase option has different base price and eventually different discounted prices.

When checking the output object of the product, the purchase option without discount has no offer ID:

        "oneTimePurchaseOfferDetailsAndroid": [
            {
                "formattedPrice": "₱430.00",
                "offerTags": [
                    "test-tag"
                ],
                "offerToken": "sample-token-set",
                "priceAmountMicros": "430000000",
                "priceCurrencyCode": "PHP"
            },
            ... other offers
        ],

The purchase option with discount has an offer ID, and inherits the tag of the base price:

            {
                "discountDisplayInfo": {
                    "percentageDiscount": 1
                },
                "formattedPrice": "₱425.70",
                "fullPriceMicros": "430000000",
                "limitedQuantityInfo": {
                    "maximumQuantity": 1,
                    "remainingQuantity": 1
                },
                "offerId": "test-offer",
                "offerTags": [
                    "test-tag"
                ],
                "offerToken": "sample-token",
                "priceAmountMicros": "425700000",
                "priceCurrencyCode": "PHP",
                "validTimeWindow": {
                    "endTimeMillis": "1769817600000",
                    "startTimeMillis": "1769731200000"
                }
            }

From Android documentation, there is no specific mention that this type has no offer ID.

Is this expected that there is no offer ID for the base price purchase option from Google Play?

[gitdogdev[bot]]

@simmotde This is expected behavior from Google Play Billing Library, not a library issue.

What's happening:
The offerId field in ProductAndroidOneTimePurchaseOfferDetail is optional (offerId?: string | null) because:

1. Base price (no discount) = No offer ID

   • Google Play represents the base/default price without an explicit offer
   • No offerId is assigned by Google Play

2. Discounted price = Has offer ID

   • When a discount is applied, Google Play creates a promotional offer
   • This offer gets an offerId (e.g., 'test-offer')
   • The offer inherits tags from the base price

From Google Play Billing Library:
According to the Android Billing Library documentation, the getOfferId() method can return null for base prices because they don't represent promotional offers—they're the standard pricing.

In react-native-iap (v14.6.0+):
The type definition reflects this:

interface ProductAndroidOneTimePurchaseOfferDetail {
  offerId?: string | null;  // ← Optional because base price has no ID
  priceCurrencyCode: string;
  priceAmountMicros: string;
  formattedPrice: string;
  // ... other fields
}

Why your code needs adjustment:

If you're checking offerId to determine pricing logic, you need to handle both cases:

const offer = productDetails.oneTimePurchaseOfferDetail;

// ❌ Don't do this:
if (offer.offerId) { /* assume it's a discount */ }

// ✅ Do this instead:
if (offer.offerId) {
  console.log('This is a promotional offer:', offer.offerId);
} else {
  console.log('This is the base price (no promotional offer)');
}

// Both have valid pricing:
console.log('Price:', offer.formattedPrice);  // Works for both

Key takeaway:

• offerId being null/undefined is not an error—it's the normal state for base prices
• Always use formattedPrice or priceAmountMicros for displaying prices, regardless of offerId
• Only use offerId if you specifically need to identify promotional offers

This matches Google Play's billing model where base prices don't require offer IDs.

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