Render threadables

app/javascript/controllers/rollup_controller.js

@@ -0,0 +1,33 @@
+import { Controller } from "@hotwired/stimulus"
+
+export default class extends Controller {
+  static targets = [ "boostEvent" ]
+
+  connect() {
+    this.#summarizeBoosts()
+  }
+
+  #summarizeBoosts() {
+    const el = document.createElement("span")
+    el.textContent = this.#boostSumaries.toSentence()
+    this.element.appendChild(el)
+  }
+
+  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
+    }, {})
+  }
+}