Angular SPA SSR Template compile error with Angular 6

[speige]

@SteveSandersonMS
Migrated from aspnet/JavaScriptServices#1619

Describe the bug

Angular SPA SSR Template compiler error with Angular 6+

To Reproduce

Steps to reproduce the behavior:
Clone https://github.com/speige/Angular6DotNetCoreSpaTemplateBug
The "master" branch is the original angular 5 template. The "Angular6Working" branch is an straight upgrade to v6 with the @angular-devkit/build-angular npm package on 0.5.5. The "Angular6broken" branch is identical except with @angular-devkit/build-angular on 0.5.6

Expected behavior

Website builds & runs

Screenshots

Additional context

Although this looks like an Angular bug, it's actually a bug in SPA AspNetCore code. The output of the Angular compiler changed slightly between v5 & v6 which made this previously masked bug in AspNetCore appear. Essentially EventedStreamReader.cs doesn't send last line's contents to listener, so it doesn't know that AngularCliBuilder is complete.

On a side note, for Angular6 upgrade, a change should be done in
https://github.com/aspnet/JavaScriptServices/blob/dev/src/Microsoft.AspNetCore.SpaServices.Extensions/AngularCli/AngularCliBuilder.cs

            var npmScriptRunner = new NpmScriptRunner(
                sourcePath,
                _npmScriptName,
                "--watch",
                null);

The "--watch" is no longer a valid command line argument in Angular 6 CLI. If you do "ng serve" it automatically does --watch, if you do "ng build" it doesn't.

I worked around this issue by changing the "build:ssr" command in my package.json from

 "build:ssr": "ng build --configuration=production --project=ssr"

to

    "build:ssr_ignore_dash_dash_watch_from_AngularCliBuilderDotCS": "ng build --configuration=production --project=ssr ",
    "build:ssr": "npm run build:ssr_ignore_dash_dash_watch_from_AngularCliBuilderDotCS"

which basically causes the extra command line argument to be discarded before "ng build" is called. Otherwise Angular throws an error about an invalid command line argument.

[mkArtakMSFT]

@ryanbrandenburg have a look and see whether this still makes sense. If yes, review the PR and merge as necessary.

[mkArtakMSFT]

We're closing this as per announcement #12890