Чтобы исправить это,
Убедитесь, что ваши зависимости
зависимости:
"@angular/common": "8.2.13",
"@angular/core": "8.2.13",
"@angular/forms": "8.2.13",
"@angular/platform-browser": "8.2.13",
"@angular/platform-browser-dynamic": "8.2.13",
"@angular/pwa": "^0.803.23",
"@angular/router": "8.2.13",
"@angular/service-worker": "^8.2.14",
dev dependencies:
"@angular-devkit/architect": "^0.803.23",
"@angular-devkit/build-angular": "^0.803.23",
"@angular-devkit/core": "^8.3.23",
"@angular-devkit/schematics": "^8.3.23",
"@angular/cli": "^8.3.23",
"@angular/compiler": "8.2.13",
"@angular/compiler-cli": "8.2.13",
"@angular/language-service": "^8.2.14",
"@ionic/angular-toolkit": "^2.1.2",
, в частности, обратите внимание, 8.2.13 для angular вместо 8.1, который я было.
Также взгляните на: https://github.com/ionic-team/ionic/issues/20341