Chart.js not displaying

Question

I am using Chart.js and Flask to make a dashboard.
I am trying to make a chart.js graph based on the response posted from the form. However, when I try creating the Chart.js graph it does not appear.
Can someone please tell me what I am doing wrong? Thanks!

Flask Code:

from flask import Flask, render_template, request
import data_analysis as analysis

app = Flask(__name__)
df = analysis.initialize()

@app.route('/')
@app.route('/home')
def home():
    return render_template('data.html', title="title", df=df.head())

@app.route('/dashboard', methods = ['POST', 'GET'])
def dashboard():
    column_name = str(request.form.get('select1'))

    # default use first column
    data = analysis.create_count_bars(df.columns[0])
    labels = list(data[0].keys())
    values = list(data[0].values())

    # else
    if (column_name != "None"):
        data = analysis.create_count_bars(column_name)
        labels = list(data[0].keys())
        values = list(data[0].values())
    return render_template('dashboard.html', title="title", df=df.head(), labels=labels,
 values=values, xlabel = data[1], ylabel = data[2], column_name=column_name)

HTML/ Chart.js Code ("dashboard.html"):

{% block header %}
<script src="https://cdn.jsdelivr.net/npm/chart.js"></script>
{% endblock %}

{% block menubar %}
<div class="navbar">
    <ul> 
        <li><a href="/home"> Home </a></li>
        <li><a class="active" href="/dashboard"> Dashboard </a></li>
    </ul>
  </div>
{% endblock %}

{% block content %}
<div id = "survey">
  <form method="POST" action="{{ url_for('dashboard') }}">
    <label for="Columns">Choose a column to graph: </label>
    <select name="select1" id="select1">
        {% for column in df %} 
        <option value="{{column}}">{{column}}</option>
        {% endfor %}
    </select>
    <br><br>
    <input type="submit" value="Submit">
  </form>
</div>

<div class="charts">
  <canvas id="barChart" width="600" height="400"></canvas>
</div>
{% endblock %} 

{% block script %}
<script>
  const ctx = document.getElementById("barChart").getContext("2d");

  const labels = [{{ labels|safe }}];

  const data = {
    labels: labels,
    datasets: [{
      label: {{ ylabel|safe }},
      backgroundColor: '#CE3B21',
      borderColor: 'rgb(255, 99, 132)',
      data: {{ values|safe }},
    }]
  };

  const config = {
    type: "bar",
    data: data,
    options: {
      responsive: true,
      scales: {
        y: {
          beginAtZero: true
        }
      }
    }
  };

  const chart = new Chart(ctx, config);
  chart
</script>
{% endblock %}