Answered Read modTemplateVarResource in modRestController - RESTful api

<?php
class myControllerPosts extends modRestController{
    public $classKey = 'modResource';
    public $defaultSortField = 'id';
    public $defaultSortDirection = 'DESC';
	
	
    public function read($id) {
        if (empty($id)) {
            return $this->failure($this->modx->lexicon('rest.err_field_ns',array(
                'field' => $this->primaryKeyField,
            )));
        }
        /** @var xPDOObject $object */
        $c = $this->getPrimaryKeyCriteria($id);
        $this->object = $this->modx->getObject($this->classKey,$c);
		
        if (empty($this->object)) {
            return $this->failure($this->modx->lexicon('rest.err_obj_nf',array(
                'class_key' => $this->classKey,
            )));
        }
		
	$tvID = 17;
	$tv = $this->modx->getObject('modTemplateVarResource', array('tmplvarid' => $tvID, 'contentid' => $id));
		
		
				
$objectArray = Array();
$objectArray ['id']  = $id;
$objectArray ['pagetitle']  = $this->object->pagetitle;
$objectArray ['alias']  = $this->object->alias;
		
			
        $objectArray ['someTV'] = $tv->value;
		

        $afterRead = $this->afterRead($objectArray);
        if ($afterRead !== true && $afterRead !== null) {
            return $this->failure($afterRead === false ? $this->errorMessage : $afterRead);
        }

        return $this->success('',$objectArray);
    }

   
}

{"message":"","object":{"id":"6","pagetitle":"someTitle","alias":"someAlias","someTV":null},"success":true}

$objectArray ['someTV'] = $tv->get('value');