person66 person66 - 2 months ago 14
Node.js Question

Check if an object is empty in Nunjucks

So I'm using Nunjucks as the templating engine in my Node.js application.

I have an object we'll call

var
which may or may not be empty.

When it is empty, if I do
{{ var | dump }}
Nunjucks properly shows that it is an empty object, displaying
{}
.

The problem is, I can't find any way to check if the object is empty using Nunjuck's
{% if condition %}
statement. I have tried
var.length
,
var | length
,
var | first
, and just plain
var
for the condition, but none of them work, they all just evaluate to true (or false), regardless of whether or not
var
is empty. Does anyone know how to solve this?

EDIT: using
{% if var | dump != '{}' %}
does work, but seems like a really hacky solution...

EDIT 2: I ended up just creating a custom
empty
filter for objects which does what I need:

env.addFilter('empty', function(object) {
return Object.keys(object).length === 0;
});

Answer

Support for accessing an object's length with the length filter was recently added in Nunjucks 2.5.0.

So you can now use:

{% if var|length %}