Openshift route does not work without trailing slash using Nginx

I have deployed my AngularJS application in Openshift 4.3. We have created route to launch application. While creating route we gave hostname and path.So route created is https://pts-dev.exmaple.com/pts-ui. But when I try to launch application using route it does not work unless and until I add trailing slash to URL https://pts-dev.exmaple.com/pts-ui. It should actually append trailing slash automatically and should launch application. So to make it work I just edited below part in my Nginx conf file and the URL .

location / {
   try_files $uri /pts-ui/index.html;
}

Initially I had the location like below with $uri/ which I removed in above snippet.

location / {
   try_files $uri $uri/ /pts-ui/index.html;
}

I am unable to understand how removing uri/ made it worked? Can anyone explain me this?