LRU cache

The cache parameter has been added to the SDK configuration and is designed to control the LRU cache for media resources (images, videos and other binary data).
This cache is used when the standard HTTP cache is unavailable (e.g., in limited WebView environments) and enables prefetching and faster access to stored resources.

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What is LRU cache?

LRU (Least Recently Used) is a cache management algorithm that removes the least recently accessed items when the cache reaches its maximum size. This ensures that the most frequently or recently used resources remain available for fast retrieval, while older or rarely used ones are automatically evicted to free up space.

In this SDK, the LRU cache mechanism ensures optimal use of local storage (memory or IndexedDB) for storing media resources, improving performance and reducing network requests.

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Properties

Field	Type	Default	Description
type	"memory" | "indexeddb"	"indexeddb"	Type of cache storage. • memory — in-memory caching (fast but temporary). • indexeddb — persistent BLOB-based cache using IndexedDB.
maxSize	number	20	Maximum cache size (in bytes or number of elements, depending on implementation).
ttl	number	0 (infinite)	Resource lifetime in the cache (in seconds). After expiration, resources may be refreshed or overwritten.
debug	boolean	false	Enables cache operation logging (useful for debugging).
concurrency	number	5	Maximum number of parallel requests for loading or caching.
prefetch	boolean	true	Indicates whether resources should be prefetched (e.g., before stories are displayed).

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How It Works

• The cache is implemented using BLOB objects.
• IndexedDB is used for persistent storage (when type: "indexeddb" is selected).
• If IndexedDB is unavailable or type: "memory" is used, data is stored in process memory.
• When prefetch is enabled, the SDK automatically preloads media resources to minimize latency during story display.

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Example

 import { IASContainer } from "@inappstory/js-sdk";

 const inAppStoryManager = new window.IAS.InAppStoryManager({
    apiKey: "{projectToken}",
    cache: {
      type: "indexeddb",
      maxSize: 100,
      ttl: 3600, // 1 hour
      debug: true,
      concurrency: 5,
      prefetch: true,
    },
  };)

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Recommendations

• Use indexeddb for persistent storage and offline access.
• Set ttl if periodic cache updates are needed.
• Enable debug only in development mode (may affect performance).
• Tune concurrency to optimize performance under heavy load.
• Enable prefetch to improve UX on slow networks.

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Purpose

This caching mechanism provides:

• Reliable SDK operation in environments without standard HTTP caching.
• Faster content display through local resource storage.
• Offline access to media assets.
• Reduced network load on repeated requests.