PRO: Use of _context in twig-templates

JSON which is a Array of Objects has to be treated in a special way. Or describe it in another way: An Array [...] contains several {...} Objects. Like this example:

[{
  "id" : 1696,
  "title" : "1Experiment Your Way Through Change",
  "type" : 14},
 {
     "id" : 2696,
  "title" : "2Experiment Your Way Through Change",
  "type" : 24}
 ]

To loop through the Objects you can use “_context” in the twig-template:

{% for key, value in _context %}
    key: {{key}}

    value: {{value | json_encode}}

    id: {{value.id}}

{% endfor %}

The result is not exactly what you expect! The loop runs through three items, not the two of the JSON. The 3rd item is the complete JSON.

---

Alter the twig-template by replacing _context by _parent:

{% for key, value in _parent %}
    key: {{key}}

    value: {{value | json_encode}}

    id: {{value.id}}

{% endfor %}

Result: Only the two expected items. But…

---

If you do some additional twig in the template, esp. adding a variable this is added to _parent and _context. Try this:

{% set aVariable="whatever" %}
{% for key, value in _context %}
    key: {{key}}

    value: {{value | json_encode}}

    id: {{value.id}}

{% endfor %}
aVariable: {{ _context.aVariable}}

The result: Four items! The Variable created by “set” is added to _context and is thus available in the twig-template by “_context.aVariable” and “aVariable”. As you only want two items, you must separate the wanted from the unwanted items by a if-statement like this:

{% set aVariable="whatever" %}
{% for key, value in _context %}
    {% if value.id %}  
        key: {{key}}

        value: {{value | json_encode}}

        id: {{value.id}}

    {% endif %}
{% endfor %}

---

In Action:
key: 0
value: {“id”:1696,”title”:”1Experiment Your Way Through Change”,”type”:14}
id: 1696

---

key: 1
value: {“id”:2696,”title”:”2Experiment Your Way Through Change”,”type”:24}
id: 2696

---