src/Eloquent/Concerns/IncludesModels.php
protected function convertIncludePath($path)
    {
        if (array_key_exists($path, $this->includePaths)) {
            return $this->includePaths[$path] ?: null;
        }

        return collect(explode('.', $path))->map(function ($segment) {
            return $this->modelRelationForField($segment);
        })->implode('.');
    }
protected function convertIncludePath($path)
    {
        if (array_key_exists($path, $this->includePaths)) {
            return $this->includePaths[$path] ?: null;
        }

        return collect(explode('.', $path))->map(function ($segment) {
            return $this->modelRelationForField($segment);
        })->implode('.');
    }
Convert a JSON API include path to a model relationship path.

@param $path
@return string|null