ngx-color-picker | Color picker widget for the Angular | Widget library

As misha130 suggested in the comments, there was (a single) library not aligned with the latest Ivy changes which was causing the error. I was fortunate enough to not have a lot of dependencies in the project, so I went through each one and uninstalled it until the app started without errors.

You seem to be using Windows cmd to run the command, and hence you are getting the error.

The command:

following @Batajus's response about compatibility, i could fix this problem with these steps:

1. Delete node_module folder
2. Delete package-lock.json
3. Run npm i
4. finally npm i -D @angular-devkit/core@0.3.2 (angular-devkit/core should be 0.3.2 for Angular V5)

@zerohouse/router-tab isn't compatible with angular 9, you have to install @cativo/router-tab to get it work.

I've just used the ng serve command :

Did you ensure that the versions of karma, karma-chrome-launcher, karma-cli, karma-firefox-launcher, (all other karma packages) and jasmine packages were the same between the fresh Angular 12 version and your project? And then did you run a fresh npm install after making sure the versions are the same?

After that, try comparing test.ts, angular.json and tsconfig.spec.json between the fresh project and your project to ensure they are the same.

try yarn install instead of npm install

To install yarn use below code

npm install --global yarn

Most likely this is related with Firebase. Try to:

• Limit the use of valueChanges() using take(1) or some similar operation. For testing purposes, you could replace your entire call to firebase with a mock call that returns an observable or a promise that immediately completes. If it worked, it means your problem is in the call to the database.
• Use different versions of firebase and @angular/fire.

Angular Universal runs your code on the server. If your code generates any async operations or observables that never complete, your server will hang forever as it is waiting for the operation to complete.

valueChanges() is necessary on the client to have a "live" stream and reflect DB changes to the UI in realtime. On the server however, this behavior is the opposite of what you need, as you would probably want to fetch some data and render the page.

Your code should detect whether it's running on a browser or on the server and create the appropriate observable (one that completes after the first emission for server, one that stays open for browsers).

💡 NOTE valueChanges() is a common problem in this case, but the same concept applies to any other observable you might have subscribed to in your code.

📦 TIP You could use UniversalService from the @bespunky/angular-zen library. Just install the library and inject the service where you need it.

At some point, there was a version of @angular/fire which had a bug where the library had internally left an operation uncompleted, in turn causing a never completing NgZone task.

The solution was either upgrading or downgrading, but you had to find the matching firebase version.

I was able to fix the problem by upgrading some of the core dependencies manually like this: