Clarify LRUCache usage (#76)

Author: Arthur Bond

CHANGELOG.md

@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ## [Unreleased]
 
+### Added
+
+- Clarification about `LRUCache` usage
+
 ## [0.2.21] - 2023-02-24
 
 ### Fixed

node/clients/status.ts

@@ -19,4 +19,14 @@ export default class Status extends ExternalClient {
       metric: 'status-get-raw',
     })
   }
+
+  public async getStatusAndForceMaxAge(
+    status: number
+  ): Promise<IOResponse<string>> {
+    return this.http.get(status.toString(), {
+      // when using an LRUCache, this will force the response to be cached
+      forceMaxAge: 5000,
+      metric: 'status-get-forceMaxAge',
+    })
+  }
 }

node/index.ts

@@ -8,7 +8,11 @@ import { validate } from './middlewares/validate'
 const TIMEOUT_MS = 800
 
 // Create a LRU memory cache for the Status client.
+// The 'max' parameter sets the size of the cache.
 // The @vtex/api HttpClient respects Cache-Control headers and uses the provided cache.
+// Note that the response from the API being called must include an 'etag' header
+// or a 'cache-control' header with a 'max-age' value. If neither exist, the response will not be cached.
+// To force responses to be cached, consider adding the `forceMaxAge` option to your client methods.
 const memoryCache = new LRUCache<string, any>({ max: 5000 })
 
 metrics.trackCache('status', memoryCache)