Adding where conditions to resource parameters

ResourceRegistrar.php

<?php

    public function register($name, $controller, array $options = [])
    {
        ...

        // We need to extract the base resource from the resource name. Nested resources
        // are supported in the framework, but we need to know what name to use for a
        // place-holder on the route parameters, which should be the base resources.
        $base = $this->getResourceWildcard(last(explode('.', $name)));

        $defaults = $this->resourceDefaults;

        foreach ($this->getResourceMethods($defaults, $options) as $m) {
            $this->addWheres(
                $this->{'addResource'.ucfirst($m)}($name, $base, $controller, $options),
                $options
            );
        }
    }

    /**
     * Add any parameter patterns to the route.
     *
     * @param  \Illuminate\Routing\Route $route
     * @param  array  $options
     * @return \Illuminate\Routing\Route
     */
    protected function addWheres($route, array $options = [])
    {
        if (empty($options['where'])) {
            return $route;
        }

        if (isset($this->wheres)) {
            $wheres = $this->wheres;
        } else {
            $wheres = $options['where'];

            $keys = array_map(function ($item) {
                return $this->getResourceWildcard($item);
            }, array_keys($wheres));

            $this->wheres = $wheres = array_combine($keys, $wheres);
        }

        return $route->where($wheres);
    }