Introduce constants for ping estimation and extract logging out of pi…

…ng class

client/index.ts

@@ -11,7 +11,13 @@ const socket: ClientSocket = io(uri, {
   },
 })
 
-new Ping(socket).start()
+const ping = new Ping(socket)
+ping.start()
+
+setInterval(() => {
+  // eslint-disable-next-line no-console
+  console.debug(`Ping: ${ping.average}ms ±${ping.delta}ms`)
+}, 60000)
 
 socket.emit('characterList', (characters) => {
   // eslint-disable-next-line no-console

client/ping.ts

@@ -1,5 +1,9 @@
 import { ClientSocket } from './socket'
 
+const initialDelay = 1000
+const delayBetweenPings = 10000
+const keepRecentPingCount = 10
+
 const avg = (values: number[]) => values.reduce((a, b) => a + b) / values.length
 
 export default class Ping {
@@ -9,9 +13,18 @@ export default class Ping {
 
   readonly #pings: number[]
 
+  #average: number
+
+  #delta: number
+
+  #isDirty: boolean
+
   constructor(socket: ClientSocket) {
     this.#socket = socket
     this.#pings = []
+    this.#average = NaN
+    this.#delta = NaN
+    this.#isDirty = false
   }
 
   #update() {
@@ -20,27 +33,44 @@ export default class Ping {
     this.#socket.emit('ping', () => {
       this.#pings.push(Date.now() - start)
 
-      while (this.#pings.length > 10) {
+      while (this.#pings.length > keepRecentPingCount) {
         this.#pings.shift()
       }
 
-      // TODO: make calculations on demand and extract/remove logging of ping
-      const ping = Math.round(avg(this.#pings))
-      const delta = Math.round(avg(this.#pings.map((d) => Math.abs(d - ping))))
-
-      // eslint-disable-next-line no-console
-      console.debug(
-        `Ping: ${ping}ms ±${delta}ms (${JSON.stringify(this.#pings)})`,
-      )
+      this.#isDirty = true
     })
 
-    this.#timeout = setTimeout(this.#update.bind(this), 10000)
+    this.#timeout = setTimeout(this.#update.bind(this), delayBetweenPings)
+  }
+
+  #updateCache() {
+    this.#average = Math.round(avg(this.#pings))
+    this.#delta = Math.round(
+      avg(this.#pings.map((d) => Math.abs(d - this.#average))),
+    )
+    this.#isDirty = false
+  }
+
+  get average(): number {
+    if (this.#isDirty) {
+      this.#updateCache()
+    }
+
+    return this.#average
+  }
+
+  get delta(): number {
+    if (this.#isDirty) {
+      this.#updateCache()
+    }
+
+    return this.#delta
   }
 
   start() {
     this.stop()
 
-    this.#timeout = setTimeout(this.#update.bind(this), 1000)
+    this.#timeout = setTimeout(this.#update.bind(this), initialDelay)
   }
 
   stop() {