There a two approaches when you need to pass a twig variable to an external javascript file
- Define the variables inside a script block in the twig template
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<script>
var my_twig_var = {% if twig_var is defined %}'{{ twig_var }}'{% else %}null{% endif %}
</script>
<script src="scripts/functions.js"></script>
</body>
</html>
For this approach I usally add a block called “javascript” block in my main/base template
base.twig.html
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
{% block body %}
{% endblock %}
{% block javascript %}
{% endblock %}
</body>
</html>
page.html.twig
{% extends base.twig.html %}
{% block body%}
<h1>Hello World</h1>
{% endblock %}
{% block javascript %}
<script>
alert('{{ twig_var|default('Hello World') }}');
</script>
{% endblock %}
- Pass the variables to javascript with the aid of
data-*attributes
<div data-foo="{{ foo }}">...</div>
$(function() {
$(document).on('click', '.button', function(e) {
console.log($('div[data-foo]').data('foo'));
});
});
Sidenote: if you want to pass an object or an array to twig you can always use the json_encode filter, which will convert the variable to a valid javascript object
If you want to have control over which object properties are exposed by the json_encode filter you can always implement the interface Serializable