Remove remaining rollup references

app/javascript/controllers/event_summary_controller.js

@@ -0,0 +1,40 @@
+import { Controller } from "@hotwired/stimulus"
+
+export default class extends Controller {
+  static targets = [ "boostEvent" ]
+
+  connect() {
+    this.#summarizeBoosts()
+  }
+
+  #summarizeBoosts() {
+    if (this.#isBoosted) {
+      const el = document.createElement("span")
+      el.dataset.turboTemporary = ""
+      el.textContent = this.#boostSumaries.toSentence()
+      this.element.appendChild(el)
+    }
+  }
+
+  get #isBoosted() {
+    return this.hasBoostEventTarget
+  }
+
+  get #boostSumaries() {
+    return Object.entries(this.#boostsByCreator).map(([_creatorId, boostEvents]) => {
+      return `${boostEvents[0].dataset.creatorName} +${boostEvents.length}`
+    })
+  }
+
+  get #boostsByCreator() {
+    return this.boostEventTargets.reduce((acc, target) => {
+      const creatorId = target.dataset.creatorId
+
+      if (!acc[creatorId]) acc[creatorId] = []
+
+      acc[creatorId].push(target)
+
+      return acc
+    }, {})
+  }
+}