Use a map to store hypercores

index.js

@@ -1,6 +1,8 @@
+const b4a = require('b4a')
+
 class HypercoreStats {
   constructor ({ cacheExpiryMs = 5000 } = {}) {
-    this.cores = []
+    this.cores = new Map()
     this.cacheExpiryMs = cacheExpiryMs
 
     // DEVNOTE: We calculate the stats all at once to avoid iterating over
@@ -20,7 +22,15 @@ class HypercoreStats {
   }
 
   addCore (core) {
-    this.cores.push(core)
+    if (!core.key) {
+      throw new Error('Can only add a core after its key is set (await ready)')
+    }
+
+    // Note: if a core with that key was already added,
+    // it gets overwritten
+    // DEVNOTE: this assumes we do not add any state to the hypercores
+    // (so no event handlers)
+    this.cores.set(b4a.from(core.key, 'hex'), core)
   }
 
   get totalCores () {
@@ -129,7 +139,7 @@ class HypercoreStats {
       return this._cachedStats
     }
 
-    this._cachedStats = new HypercoreStatsSnapshot(this.cores)
+    this._cachedStats = new HypercoreStatsSnapshot([...this.cores.values()])
     this._lastStatsCalcTime = Date.now()
     return this._cachedStats
   }

package.json

@@ -27,9 +27,10 @@
     "corestore": "^6.18.4",
     "hypercore": "^10.37.19",
     "prom-client": "^15.1.3",
+    "random-access-memory": "^6.2.1",
     "standard": "^17.1.0"
   },
   "dependencies": {
-    "random-access-memory": "^6.2.1"
+    "b4a": "^1.6.6"
   }
 }

test.js

@@ -10,6 +10,8 @@ test('Can register and get prometheus metrics', async (t) => {
   const store = new Corestore(RAM)
   const core = store.get({ name: 'core' })
   const core2 = store.get({ name: 'core2' })
+  await core.ready()
+  await core2.ready()
 
   const stats = new HypercoreStats()
   stats.registerPrometheusMetrics(promClient)
@@ -112,6 +114,7 @@ function getMetricValue (lines, name) {
 test('Cache-expiry logic', async (t) => {
   const store = new Corestore(RAM)
   const core = store.get({ name: 'core' })
+  await core.ready()
 
   const stats = new HypercoreStats({ cacheExpiryMs: 1000 })
   stats.registerPrometheusMetrics(promClient)