Nunjucks: Select specific items from array in for loop

Question

I need to select specific items from a large array, say [5, 21, 83, 74, 12], and my list looks like this:

{
  "list:" [
    { "title": "Blue" },
    { "title": "Green" },
    { "title": "Yellow" } ...
  ]
}

I was thinking about a for loop, but am not sure of the syntax or filters I should use. How should I modify this code to accomplish the above?

{% for item in list %}
    {% item %}
{% endfor %}

Answer 1

You can add a custom filter if you need to apply filter more than once.

var nunjucks  = require('nunjucks');
var env = nunjucks.configure();
env.addFilter('myfilter', arr => arr.filter(e => e.title == 'Green'));

var html = env.renderString(`
    {% for item in list | myfilter %} 
        {{item.id}} {{ item.title}} 
    {% endfor %}
    `, 
    { 
        list: [
            { id: 1, title: 'Blue' },
            { id: 2, title: 'Green' },
            { id: 3, title: 'Yellow' },
            { id: 4, title: 'Green' }
        ]
    }
);

console.log(html);

Another way is to use if each time

{% for item in list %}
    {{ item if item.title == 'Green' }}
{% endfor %}

or

{% for item in list %}
    {% if item.title == 'Green' %}
        {{ item }}
    {% endif %} 
{% endfor %}