element-tiptap | modern WYSIWYG rich-text editor using tiptap | Editor library

We first need to know how the request flow works in whole express and vue.js.
In your project, you're not running express and vue with same port at the same time.
More clearly, you're using express with 8080 port to host vue.js content.

In express, your request match the rule app.get("/", (req, res)= >{res.render("index")})
then express will render the index page for you when you visit the http://localhost:{port}/

And after you add "other" word in your rule app.get("/other", (req, res)= >{res.render("other")})
express will render other page for you when you visit the http://localhost:{port}/other

What if request doesn't match rule?
Express will give you a not found page.

When you host the vue output js (we call build.js here) in express server instead of webpack-server.
In your vue project, you setup the vue-router with / and /other-path.
In these paths, vue will render content of / and /other-page.

We assume you use express to host the build.js
And we need the html to include this build.js with following code.