=================
Render containers
=================

This guide shows how to output EXT:container (b13/container) elements with this extension — the container's columns as JSON alongside or inside the container's own `data`.

Prerequisites
=============

*   EXT:container installed (`composer require b13/container`)
*   Container Content Types defined (e.g. the `b13_2_columns_container` used below, with child columns `colPos` 201 and 202)

`b13/container` is a *suggested* dependency — the extension works without it; the `nb-container-json` processor only loads when EXT:container is present.

TypoScript setup
================

Variant 1: `left`/`right` parallel to `data`
--------------------------------------------

..  code-block:: typoscript

    lib.content.select.where = colPos NOT IN (201, 202)

    tt_content.b13_2_columns_container =< lib.contentElement
    tt_content.b13_2_columns_container {
        fields {
            left = TEXT
            left {
                dataProcessing {
                    10 = nb-container-json
                    10 {
                        colPos = 201
                        as = left
                    }
                }
            }
            right = TEXT
            right {
                dataProcessing {
                    10 = nb-container-json
                    10 {
                        colPos = 202
                        as = right
                    }
                }
            }
        }
    }

Result: the container element carries `left`/`right` next to `data`:

..  code-block:: json

    {
        "id": 5,
        "type": "b13_2_columns_container",
        "colPos": 0,
        "left": [ { "id": 6, "type": "vendor_text", "data": { "...": "..." } } ],
        "right": [ { "id": 7, "type": "vendor_image", "data": { "...": "..." } } ]
    }

Variant 2: `left`/`right` inside `data`
---------------------------------------

..  code-block:: typoscript

    lib.content.select.where = colPos NOT IN (201, 202)

    tt_content.b13_2_columns_container.fields.data.dataProcessing.10 {
        dataProcessing {
            10 = nb-container-json
            10 {
                colPos = 201
                as = left
            }

            20 = nb-container-json
            20 {
                colPos = 202
                as = right
            }
        }
    }

This is the sub data processor pattern from `Add sub data processors <AddSubDataprocessors.rst>`__ — the columns land as keys inside `data`.

How it works
============

`nb-container-json` (`ContainerJsonDataProcessor`) fetches the container's children for the given `colPos` via b13/container's `ContainerProcessor` and renders each child through the same conversion as `nb-content-blocks-json` — field identifiers as keys, same `JSON contract <../Reference/JsonContract.rst>`__.

Both variants are covered end-to-end by `Tests/Functional/Frontend/ContentBlocksJsonResponseTest.php`.

Container as Content Block (variant 2): keep your own fields
============================================================

When the container itself is a Content Block (variant 2), do **not** register it with `Registry::configureContainer()`: b13/container would overwrite the `types[<cType>]['showitem']` of the Content Block, and the resolved record (and thereby `data`) would lose the Content Block's own fields. Write the `containerConfiguration` directly into TCA instead — this keeps the Content Block's showitem while b13/container still recognizes the container:

..  code-block:: php

    $configuration = new \B13\Container\Tca\ContainerConfiguration(
        'vendor_mycontainer',
        'My Container',
        '',
        [[['name' => 'main', 'colPos' => 201]]]
    );
    $GLOBALS['TCA']['tt_content']['containerConfiguration']['vendor_mycontainer']
        = $configuration->toArray();

The `colPos` exclusion matters
==============================

`lib.content.select.where = colPos NOT IN (201, 202)` keeps the container children out of the regular page content query. Without it, children appear twice: once in the page's content array and once in their column.

Options
=======

The processor accepts `colPos` (container column to fetch, required) and `as` (key of the children array). Children are rendered through their own `tt_content.<CType>` mapping, so their conversion options (`processor options <../Reference/ProcessorOptions.rst>`__ like `options.processing` or `options.dateTimeFormat`) are configured there, not on `nb-container-json`.

If the container cannot be built (e.g. the record is hidden), `as` is an empty list. Children without a `renderedContent` key — e.g. with b13's `skipRenderingChildContent` and no substitute data processor — become `null` entries.