src/Repository/DynamoDb/NodeTable.php
final public function getIndex(string $alias): ?GlobalSecondaryIndex
    {
        $this->loadIndexes();
        return $this->gsi[$alias] ?? null;
    }
final public function getIndex(string $alias): ?GlobalSecondaryIndex
    {
        $this->loadIndexes();
        return $this->gsi[$alias] ?? null;
    }
final public function getIndex ( string $ alias ) : ? GlobalSecondaryIndex { $ this -> loadIndexes ( ) ; return $ this -> gsi [ $ alias ] ?? null ; }
Returns an index by its alias if it exists on this table.

@param string $alias

@return GlobalSecondaryIndex|null
Returns an index by its alias if it exists on this table .