setLeft example

// If it's a shorthand property convert the value to an assignment             // pattern if necessary             $value = $node->getValue();
            $key = $node->getKey();
            if ($value && $node->getShorthand() &&
                !$value instanceof Node\AssignmentExpression &&
                (!$value instanceof Node\Identifier || (
                $key instanceof Node\Identifier && $key->getName() !== $value->getName()
                ))) {
                $loc = $node->location;
                $valNode = $this->createNode("AssignmentPattern", $loc->start);
                $valNode->setLeft($key);
                $valNode->setRight($value);
                $this->completeNode($valNode, $loc->end);
                $value = $valNode;
            } else {
                $value = $this->expressionToPattern($value);
            }
            $retNode->setValue($value);
            $retNode->setKey($key);
            $retNode->setMethod($node->getMethod());
            $retNode->setShorthand($node->getShorthand());
            $retNode->setComputed($node->getComputed());