# JSON Helper

When creating views that return JSON, it's important to also set the appropriate response header. The JSON view helper does exactly that. In addition, by default, it disables layouts (if currently enabled), as layouts generally aren't used with JSON responses.

The JSON helper sets the following header:

    Content-Type: application/json

Most AJAX libraries look for this header when parsing responses to determine how to handle the content.

Usage of the JSON helper is very straightforward:

    <?php echo $this->json($this->data) ?>

## Keeping layouts and enabling encoding using Zend_Json_Expr

Each method in the JSON helper accepts a second, optional argument. This second argument can be a boolean flag to enable or disable layouts, or an array of options that will be passed to `Zend_Json::encode()` and used internally to encode data.

To keep layouts, the second parameter needs to be boolean `TRUE`. When the second parameter is an array, keeping layouts can be achieved by including a keepLayouts key with a value of a boolean `TRUE`.

    // Boolean true as second argument enables layouts:
    echo $this->json($this->data, true);

    // Or boolean true as "keepLayouts" key:
    echo $this->json($this->data, array('keepLayouts' => true));

`Zend_Json::encode` allows the encoding of native JSON expressions using `Zend_Json_Expr` objects. This option is disabled by default. To enable this option, pass a boolean `TRUE` to the enableJsonExprFinder key of the options array:

    <?php echo $this->json($this->data, array(
        'enableJsonExprFinder' => true,
        'keepLayouts'          => true,
    )) ?>