node_modules/ngx-toastr/toastr/toast-noanimation.component.d.ts(19,9)

I had the same issue. I've solve it by changing the toastr version in the package.json. I've used this "ngx-toastr": "^10.0.4", instead of this "ngx-toastr": "^12.0.0". And then npm i.

You just need to check that you are using the correct version of ngx-toastr for the version of Angular you are using.

ngx-toastr  Angular
6.5.0       4.x
8.10.2      5.x
10.1.0      8.x 7.x 6.x
11.3.3      8.x current >= 9.x

See the dependencies here: https://www.npmjs.com/package/ngx-toastr#dependencies

Installed "ngx-toastr": "^10.0.4" and "@angular/animations": "^8.2.14",

For angular 8 permanently fixed my issue.