Typehead.js dropdown does not appear

I have been trying to get typehead.js library to work on a dropdown list that pulls from a mysql database for a while but it has not worked. I decided to try the basics first and tried to populate the dropdown from a simple array instead of a database as shown in the typehead.js docs examples.

I created this codepen but I havent been able to get the dropdown working over there as well.

I copied the typehead.js lib to the JS section of codepen. Here is my HTML:

<!DOCTYPE html>
<html lang="en">
<head>
<title>Typehead</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css" integrity="sha384-Gn5384xqQ1aoWXA+058RXPxPg6fy4IWvTNh0E263XmFcJlSAwiGgFAW/dAiS6JXm" crossorigin="anonymous">
<script
  src="http://code.jquery.com/jquery-3.3.1.js"
  integrity="sha256-2Kok7MbOyxpgUVvAk/HJ2jigOSYS2auK4Pfzbm7uH60="
  crossorigin="anonymous"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/bootstrap-3-typeahead/4.0.2/bootstrap3-typeahead.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js" integrity="sha384-ApNbgh9B+Y1QKtv3Rn7W3mgPxhU9K/ScQsAP7hUibX39j7fakFPskvXusvfa0b4Q" crossorigin="anonymous"></script>
<style>
    .typeahead { z-index: 1051; }
</style>
  </head>

  <body>

    <div id="the-basics">
  <input class="typeahead" type="text" placeholder="States of USA">
</div>

    <script>
    var substringMatcher = function(strs) {
  return function findMatches(q, cb) {
    var matches, substringRegex;

    // an array that will be populated with substring matches
    matches = [];

    // regex used to determine if a string contains the substring `q`
    substrRegex = new RegExp(q, 'i');

    // iterate through the pool of strings and for any string that
    // contains the substring `q`, add it to the `matches` array
    $.each(strs, function(i, str) {
      if (substrRegex.test(str)) {
        matches.push(str);
      }
    });

    cb(matches);
  };
};

var states = ['Alabama', 'Alaska', 'Arizona', 'Arkansas', 'California',
  'Colorado', 'Connecticut', 'Delaware', 'Florida', 'Georgia', 'Hawaii',
  'Idaho', 'Illinois', 'Indiana', 'Iowa', 'Kansas', 'Kentucky', 'Louisiana',
  'Maine', 'Maryland', 'Massachusetts', 'Michigan', 'Minnesota',
  'Mississippi', 'Missouri', 'Montana', 'Nebraska', 'Nevada', 'New Hampshire',
  'New Jersey', 'New Mexico', 'New York', 'North Carolina', 'North Dakota',
  'Ohio', 'Oklahoma', 'Oregon', 'Pennsylvania', 'Rhode Island',
  'South Carolina', 'South Dakota', 'Tennessee', 'Texas', 'Utah', 'Vermont',
  'Virginia', 'Washington', 'West Virginia', 'Wisconsin', 'Wyoming'
];

$('#the-basics .typeahead').typeahead({
  hint: true,
  highlight: true,
  minLength: 1
},
{
  name: 'states',
  source: substringMatcher(states)
});

  </script> 
  </body>

The drop down list does not appear at all.

Solution

Seems the copy paste script might have been broken in your case. Just import it from a CDN like this

<script src="http://twitter.github.io/typeahead.js/releases/latest/typeahead.bundle.js">
</script>

Checkout this codepen