JSFiddle - React, Tailwind, and code Playground

HTML

<script src="//code.jquery.com/jquery-3.3.1.slim.min.js"></script>
<link rel="stylesheet" href="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/css/bootstrap.min.css">
<script src="//cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.0/umd/popper.min.js"></script>
<script src="//stackpath.bootstrapcdn.com/bootstrap/4.1.0/js/bootstrap.min.js"></script>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">


<div class="dropdown">
  <a class="btn btn-secondary dropdown-toggle" href="#" role="button" id="dropdownMenuButton" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
    Dropdown link
  </a>
<div class="dropdown-menu" aria-labelledby="dropdownMenuButton">
   <button class="btn btn-sm dropdown-item edit-button" data-toggle="modal" data-target="#announcementEditModal" data-id="announcement.id" data-content="announcement.content" type="button">
       <div class="announcement-actions">
          <span class="fas fa-pencil-alt"></span> Edit announcement
       </div>
  </button>
  </div>  
  </div>
  
  <div class="modal fade" id="announcementEditModal" tabindex="-1" role="dialog" aria-hidden="true">
    <div class="modal-dialog modal-lg" role="document">
        <div class="modal-content">
            <div class="modal-header announcement-header">
                <h5 class="modal-title" id="exampleModalLabel"><span class="fas fa-edit"></span> Edit new announcement</h5>
            </div>
            <div class="announcement-card-header card m-3 border-0">
                <div class="announcement-card-header card-body border-0 p-1">
                    <span class="fa fa-info-circle fa-lg header-icon"></span>
                    <h5 class="align-header">ANNOUNCEMENT TEXT</h5>
                </div>
                <div class="announcement-card-body modal-body card border-0">
                    {{ form_start(editForm) }}
                    <div class="announcement-card-body">
                       ...

CSS

.row {
  background: #f8f9fa;
  margin-top: 20px;
}

.col {
  border: solid 1px #6c757d;
  padding: 10px;
}

JavaScript

var content = ""; // global variable be careful;
  $(".edit-button").click(function(){
        content = $(this).data("content");
        alert(content);
    });

    $('#announcementEditModal').on('shown.bs.modal', function () {
        alert("modal open");
        // $("#announcementText").val(content); <-- jQuery way
        document.getElementById("announcementText").value = content;
    })