Issues with returnJson not returning html?

Question

Im running in to issues with returnJson not returning html or just returning and empty object:

$userHtml = craft()->logic->renderSiteMacro('_macros/elements', 'listing', $args);

$this->returnJson(array(
     'success' => true,
     'existing' => $userHtml
));

The return JSON is always:

{"success":true,"existing":{}}

I have double checked the html output exists and the issue persists:

• Whether returning a simple string or large chunk of html
• And with and without single quotes
• When renderSiteMacro functions runs the code through the raw filter and not

Answer 1

It appears whitespace was the cause here, just running a quick whitespace filer on the return value resolved the issue:

$userHtml = craft()->logic->renderSiteMacro('_macros/elements', 'listing', $args);

$userHtml = preg_replace('~>\\s+<~m', '><', $userHtml);

$this->returnJson(array(
    'success' => true,
    'existing' => $userHtml
));