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Angular app, Inside an Asp.Net Core Project, pros & cons

I would like to create a Single Page Web App with Angular but I couldn't decide to project type.
(Just generated files by tools like angular-cli or that generated files inside an Asp.Net Core Project)
I got some question.
What are the advantages and disadvantages of building angular app on ASP.NET Core Project?
Which cases I should prefer to locate angular app inside a ASP.NET Core Project?

I'd like to take a stab at this. I'll agree that the answer is on some part opinion based though.
I have just been comparing the two versions for a new project that I am involved in.
First some facts
The Angular project created inside of the ASP.Net core application is in no way dependant on the .Net code. You can navigate to the directory and type ng serve and run it by itself.
You can copy the angular code to another directory or repo and host it by itself if you for some reason later on decide that you don't want to combine it. All you have to do is copy paste the angular code, and then remove some lines in startup.cs regarding the internal hosting.
The code that gets added inside of the asp net core template is close to the base angular app with a few examples added on.
If you use the login functionality template it implements an oidc client, and an identity server on the back end, (opinion) pretty much the same way I would have done it myself. There is nothing stopping you from rewriting it if you don't like it. At worst it's a good example of how it can be done.
As of today the template is using Angular 8.0.0, you can just change the package.json to get the latest version and run npm install. It works great.
You can still use Visual Studio Code for the Angular parts with a combined project.
Here are when Id choose the different versions (warning opinions ahead).
When to choose the asp.net core angular project.
Small web app with limited functionality.
Small team, probably same person writing angular code as api code.
If you are unsure. You can always split later.
When to choose separate apps.
Big team with deployment builds and automation.
If you want to host angular and asp.net core separately (for reasons such as to achieve maximum performance and load balancing in apps with thousands of visitors).
Separate people coding angular and asp.net
You don't like having it all in same repo and want to split it up.
In a bigger teams and contexts with multiple APIs you will probably have to deal with CORS anyways, but if not you will have to at least think about it for this to work.
If you are unsure, you can always combine it to one app later.

How to work with hybrid webapp (MPA and SPA combined)

What are good practices about building a multiple page application using modern JS frameworks?
Multiple page application
In multiple page application we have multiple templates using some “template syntax” to provide us with backend data and AJAX (if needed) or advanced UX voodoo is often handled by jQuery.
Single page application
In single page application “backend data” is provided by AJAX requests and whole routing, frontend logic is handled by JS. We often use some JS framework like Angular or React and compile our sources with task runners/bundlers like webpack or gulp.
Hybrid application
But the most popular around the web seems to be hybrid app. What is typical build workflow while working with such an app? I could not find any tutorials or guides.
So to be specific. I imagine webapp where in which, each page has to be compiled and could share some resources. Every page has own JS routing like wizards or subcomponents. Data is loaded both during page load and AJAX.
For example my webapp would have 3 pages:
guest page - would provide website user with limited content and attract him to sign up
user - would provide signed website user with full content, resources would be extended guest content
admin - shares only styles and webapp “core”
Task Runners/Bundlers
For example in webpack is there a way to specify multiple entry and output points? Maybe the better way is to have multiple webpack/gulp configurations. In that case If I have a lot of pages I would have to write webpack/gulp configurations for every page even though some of them could be exactly the same. How to run that kind of build?
Sharing resources
Will browser load cached js bundle with the same hash like bundle.a2k4jn2.js within the same domain but different address? If so, how to specify such a behaviour in tools like webpack or gulp. I heard about CommonsChunkPlugin but not sure how to use it or even I’m looking at right direction.
Templates
What if I want to load some “backend” data not by AJAX but at the page loading. Of course every templating engine provides us with ability to write native code directly in html template like JSP or PHP. But what if some routing is handled by JS and “template tag” is not visible for page at initial loading i.e. template would not be compiled. Sometimes template engine in server and client could have the same special tag like Blade and Angular which can lead to conflicts.
Directory structure
I suppose that in hybrid app frontend and backend will be tightly coupled. Sharing JS in hybrid app could lead to very complicated imports (in es6 or html script tag). How to keep it simple.
Deploy
What about deploying an application? In java it’s easy because we just specify directories (compiled pages) in build tool (maven, gradle) which be copied to jar/war, but in PHP source code is not compiled how to keep “js source” away from production I could not imagine sensible resolution other than writing own batch/bash script
Summary
I have mentioned specific technologies and frameworks. But my question is about common approach to work with such an webapp rather than “how to do sth in that tool”. Although code examples would be greatly appreciated.

Their is a lot in this question, as a starting point you can define multiple entry points in webpack.
https://webpack.js.org/concepts/entry-points/
If you want to mix data loading between FE and BE then you really need to write an isomorphic JS application and use Node as your BE, otherwise you’ll end up writing everything twice in different languages and having once come across a project like that, trust me you really want to avoid that.
The other bit of this question on shared resources is best answered by WebPack’s bundle splitting which is made for what is being asked here
https://webpack.js.org/guides/code-splitting/

Not sure if I totally understand the question, but single-spa (yes it's redundant) is a tool that can be used to combine multiple apps (even if they are different frameworks) into one single page application. Link to the docs: https://single-spa.js.org/docs/getting-started-overview

vuejs templates als asp.net partialviews, good practice?

i'm using Vue.js in a Website and added the templates in the html Code and the js-Code in a single js-file.
So i do not want to use the *.vue <-> Vuefy/Browserfy approach but bundle and minify my js-files later.
As i have to use Asp.Net MVC i could use split the single Html-file in a view and insert the vue-div-elements hierarchically structured with #Render.Partial(...).
This way i could do a clean separation and use the same system like the *.vue files.
Would this be a good practice?
Do you think it would be better to write the html and new Vue({}) in every partial .cshtml or just write the html code there and put the javascript into (a) js-file(s).
The js-code in script-tags could not be bundled and i don't like that much inline Code but it would a nice coupling of the components code.
By using multiple js-files i could store then in the views folder next to their partial partners and bundle them together with the VS Extension Bundler and Minifier.
Are these thoughts usefull or is there still a good aproach for using vuejs templates in asp.net?
EDIT: I used to write some of the partial views with a specific Preifx. The include inline script tags, wich comes the .vue approach very close and is cool in small components because its all in one page. The inline script is conditional with Razor, so only in the dev build it gets rendered inline, for production it get's send separated. To do so I wrote a powershell script and execute it as pre-build event to exctract all the inline code into a js-file.
This file get's bundled with the other js-files and is served minified for production. So i can use all the Razor features in the html/templates and other pages of the project are just *.cshtml views.
For only-one-SPA-sites the approach mentioned by iknowitwasyoufredo sounds better.

If you use vue.js to do some simple js tasks, instead of jquery I think it is good.
But if you want to have a single page application, routing, two way binding etc. mixing asp.net mvc views with vue.js is not a good idea. Eventually, you will face many problems.
It's an architectural decision but you could implement web api services with dotnet, and use this services from a node.js application (express, webpack, vue.js).

Can single page application javascript not unloading lead to memory issues

Javascript frameworks like AnguarJs, BackboneJs, Emberjs that use to develop Single Page Applicaitons(SPA's) load lots of js files. Since these files cannot be unloaded can a application go into a situation that cause memory issues because of these js files because SPA's usually doesn't refresh the page.
For an example if application have multiple modules( eg : payroll, attendance,.. of a ERP ) SPA load js files specific to that module to browser when it get loaded. But when navigated to different module without refreshing the page previously loaded js files remain in memory. Imagining application has lots of modules like this is it possible in a certain time these js files cause memory problem ( not enough memory or corruption) ?

Keep in mind that you don't need to use a framework to create a SPA. It is true that at times Angular, React and other frameworks do create bloated code, but they also provide many useful functionality. So depending on the project you may or may not use them.
You can also load your code as modules, and load the modules when needed and unload them when you don't need them. So there is more to SPA's than just using a framework.

Things to remember before developing a Single Page Application
Try to use minified versions of JS and css files
Never use Single page approach if you are developing a large
application because when all html is renderd in single page then the
web application get heavier

AngularJS and SpringMVC in the same project

I'm writing Java Web application and want to use AngularJS on frontend.
But I don't want to delegate routing and security to angular, but handle it with spring. My file hierarchy in the project looks like that:
I wrote Angular controllers, services etc. And just apply it on the jsp page with some init parameters. All jsp are loaded by Spring controllers, I have some security rules for that pages. Angular also consumes REST API from this application.
The question is about efficiency of such approach. In fact I have a few SPA in here. Every time i load a page, Angular initializes from the beginning (there is about 10 pages).
The reasons I want to stay on this version are:
It's already set (Routing, Security)
It seems like I don't need to load all the scripts on the page, but only required ones
But also I have feeling I'm doing it wrong way...
Should I separate Spring and Angular and use Angular also for routing and security handling, not only for DOM manipulation.
What do you think? Do you have any suggestion?

Angular is not another jQuery, its Single page application framework.
You can look on SPAs like on ordinary external application which communicates with your backend. So there is no view or prezentation layer on server, just REST API.
Angular app should have its own routing, it doesn't make sense to combine it with spring MVC. Security lays mostly on REST, and you can use spring security on it as ussual.
Best practice is to create Angular app as separate javascript application. You can use a lot of tools from angular ecosystem which makes your work very comfortable.
During development you have your backend running, and develop Angular part separately using javascript devstack. After that you can pack the both parts to single war.
I have nice small example of Spring and Angular integration here:
https://github.com/Angular-cz/java-devstack
Unluckilly the readme is written in Czech (beautifull language :) But if you are experienced in Java and maven you will probably get it from code, I will also try to describe it here.
The bigger app with a nice module structure and jwt autentication can bee seen here:
https://bitbucket.org/angular_cz/beerapp
Both of them has similar architecture:
separate maven module for frontend and separate for backend.
javascript part use npm as package manager
developer is using gulp task runner for javascript development (it is run inside module, where gulpfile.js resides).
there is karma runner configured and several unit tests
the app connects to the backend during development using proxy running on /api for the app can have same configuration on production)
when building war, frontend module uses frontend-maven-plugin which run gulp build task same as javascript developer would
then the built minified assets are put to resources
the next part is just ordinary maven way how to put assets to /static
one more nice thing - there is also integrated e2e test under integration-test profile.
Feel free to ask if you are interested in this kind of architecture.