openfoodnetwork/app/webpacker/controllers/checked_controller.js

import { Controller } from "stimulus";

export default class extends Controller {
  static targets = ["all", "checkbox"];

  connect() {
    this.toggleCheckbox()
  }

  toggleAll() {
    this.checkboxTargets.forEach(checkbox => {
      checkbox.checked = this.allTarget.checked;
    });
  }

  toggleCheckbox() {
    this.allTarget.checked = this.checkboxTargets.every(checkbox => checkbox.checked);
  }
}