Compatibility of ngx-ui-scroll version 2.0.0 with Angular 7

[anasrbh]

Hello and thank you for the enormous work you have done.

I wanted to know if version 2.0.0 of the library can be compatible with Angular 7 ?

Thank you.

[dhilt]

@anasrbh Yes, it should work, I placed "ngx-ui-scroll v2 / Angular 7" demo on stackblitz, please take a look: https://stackblitz.com/edit/ngx-ui-scroll-2-with-angular-7

[anasrbh]

@dhilt Thank you for your response. I'm glad it works for angular 7. But in my case, I get error messages during compilation when I upgrade from version 1.11.1 of ngx-ui-scroll to 2.0.2. Maybe I missed something.

Here are the error messages:

Here is how I instantiated the datasource :

[dhilt]

@anasrbh Thanks for details! It seems to be a Typescript compatibility issue. The point is that vscroll is built with Typescript 4 and uses Omit helper type which was introduced in Typescript 3.5.1. The nearest Angular version supporting TS 3.5 is Angular 8.2. I would certainly not insist on updating the Angular, but it might be a good solution while I'm looking at the problem on the lib's end.

[anasrbh]

@dhilt Ok, I'll try to update Angular and see if the problem is fixed.
Do you think there is a chance that the latest version of ngx-ui-scroll might work on Angular 7 ?

[dhilt]

@anasrbh Omit is not the only problem, I'm afraid. I can get rid of TS Omit, but "ambient context" is much more painful thing, there was a breaking change introduced in TS 3.7 -- microsoft/TypeScript#33939 -- it made 3.7+ compiled code incompatible with the code compiling by the previous (3.7-) TS versions. And Angular 8 will not help, only Angular 9 will. I need to think... fixing this on the lib's end might be quite expensive. But let's not rush to conclusions.

Meanwhile there is a simplest workaround, you may turn the external libs checking off by adding the following to your tsconfig.json:

"skipLibCheck": true,

This will degrade type checking, but will allow to compile incompatible TS pieces.

[anasrbh]

@dhilt I added the "skipLibCheck" option to tsconfig. This certainly made the "TS Omit" and "ambient context" errors disappear.
But there is always a compilation error following the instantiation of the datasource.

This may be due to the new type of the adatper variable in the datasource constructor :

Maybe i need to update angular to at least version 8.2 to get rid of this error message.

I was also wondering is there a real change between version 1.11.1 and 2.0.2 ?

Thank you.

[dhilt]

@anasrbh The main purpose of v2 release is extracting the core into a separate framework-independent npm package vscroll, which is going to be used outside the Angular universe. It was accompanied with multiple infrastructure updates, and in particular vscroll uses TS4.

I just pushed a new tiny Angular7 project with ngx-ui-scroll v2 and skipLibCheck setting into Github, for me it works as expected, both "start" and "build" scripts: https://github.com/dhilt/angular-7-ngx-ui-scroll-2. Please try it? There might be an important difference in the lib usage between your home.component.ts and the demo's app.component.ts.

[anasrbh]

@dhilt Thank you for taking the time to create the project on Github. You are right, it works well. And when I returned back to my project, I uninstalled and reinstalled ngx-ui-scroll and I no longer see the error related to instantiating the datasource.

However, I see errors when I try to use the adapter functions (relax, reload, check ...) :

I think this is normal as the adapter is of type IAngularAdapter which extends Omit <IAdapter , keyof IReactiveOverride>. As Omit is not recognized by typescript versions lower than 3.5.1. This must have generated the error :

What do you think ?

[dhilt]

@anasrbh Well, I cleaned up the code from all incompatible TS expressions except "ambient context", which should be covered by skipLibCheck option. Please try ngx-ui-scroll v2.0.3 with skipLibCheck.

[anasrbh]

@dhilt Thank you so much ! I installed the new version and added skipLibCheck and it works fine.
I know it's just a temporary pseudo solution but it seems to be enough to make the virtual scroll work well in my case.

I close the ticket wishing you good luck for further improvements in this library.

Have a good day !