Dot notation in Nunjucks sorting isn't working

Question

I'm using Eleventy (11ty) with Nunjucks. I have some JSON data that I am trying to sort. The Jinja documentation says that you can sort by attribute using dot notation, but when I try sorting by address.city, nothing happens:

{% for item in testData|sort(attribute="address.city") %}
  {{ item.name }}
{% endfor %}

It does work if I sort without dot notation/by a top level field (name):

{% for item in testData|sort(attribute="name") %}
  {{ item.name }}
{% endfor %}

My test data (testData.json):

[
  {
    "name": "AAA",
    "address":
    {
      "city": "A?"
    },
    "salary": 2,
    "married": true
  },
  {
    "name": "III",
    "address": {
      "city": "D?"
    },
    "salary": 1,
    "married": true
  }
]

Answer 1

So, as seen in the comments to my question, sorting by dot notation isn't supported in Nunjucks currently.

What I did in the end, to get what I needed in my Nunjucks template in Eleventy, was to create a custom filter, inside of .eleventy.js, along the lines of:

eleventyConfig.addFilter("sortByCity", arr => {
  arr.sort((a, b) => (a.address.city) > (b.address.city) ? 1 : -1);
  return arr;
});

Then, in my Nunjucks template:

{% for item in testData | sortByCity %}
  {{ item.name }}
{% endfor %}

I know this answer is more 11ty-specific, but I think this could quite possibly work for other environments to extend Nunjucks. Hopefully this will be of help to someone else in the future. Nunjucks docs about Filters are here