miloschuman\highcharts\SeriesDataHelper::normalizeColumns PHP Method

    protected function normalizeColumns()
    {
        $formatters = $this->getFormatters();
        foreach ($this->columns as $index => $column) {
            // convert shorthand string and int configs to array
            if (is_string($column)) {
                $column = explode(':', $column);
            } elseif (is_int($column)) {
                $column = [$column];
            }
            // default to 'raw' formatter if none is specified
            if (!isset($column[1])) {
                $column[1] = 'raw';
            }
            // assign built-in formatters
            if (!is_callable($column[1])) {
                if (array_key_exists($column[1], $formatters)) {
                    $column[1] = $formatters[$column[1]];
                } else {
                    throw new InvalidConfigException("Invalid formatter for column: {$column[0]}.");
                }
            }
            $this->columns[$index] = $column;
        }
    }