visual studio - How to resolve this build error in Angular 8 ASP.NET

Question

I get this error Cannot find module '@angular/core'. and search SO for help on this and there are questions but nothing helps me.

Does this has to do with wrong version import? In the command windows I run

L:NetProjectBooksProjectBooksProjectClientApp>ng build

and get the same error

BooksProject> 
BooksProject> fail: Microsoft.AspNetCore.SpaServices[0]
BooksProject>       ERROR in ../../../node_modules/@angular/cdk/bidi/typings/dir-document-token.d.ts(8,32): error TS2307: Cannot find module '@angular/core'.
BooksProject>       ../../../node_modules/@angular/cdk/bidi/typings/dir.d.ts(8,59): error TS2307: Cannot find module '@angular/core'.
BooksProject>       ../../../node_modules/@angular/cdk/bidi/typings/directionality.d.ts(8,41): error TS2307: Cannot find module '@angular/core'.
BooksProject>       ../../../node_modules/@angular/cdk/text-field/typings/autofill.d.ts(9,69): error TS2307: Cannot find module '@angular/core'.
BooksProject>       ../../../node_modules/@angular/cdk/text-field/typings/autofill.d.ts(10,28): error TS2307: Cannot find module 'rxjs'.
BooksProject>       ../../../node_modules/@angular/cdk/text-field/typings/autosize.d.ts(8,71): error TS2307: Cannot find module '@angular/core'.
BooksProject> 

If I debug the app a get browser window with only the text, "Cannot GET /"

I deleted the node_modules folder and did npm install

I run the command after suggestion from @HariniP, Thanks!

npm i @angular/core

And this is the output, do I need to fix all this WARN?

L:NetProjectBooksProjectBooksProjectClientApp>npm i @angular/core
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN @angular/[email protected] requires a peer of @angular/[email protected] but none is installed. You must install peer dependencies yourself.
npm WARN The package protractor is included as both a dev and production dependency.
npm WARN The package ts-node is included as both a dev and production dependency.
npm WARN The package tslint is included as both a dev and production dependency.
npm WARN optional SKIPPING OPTIONAL DEPENDENCY: [email protected] (node_modulesfsevents):
npm WARN notsup SKIPPING OPTIONAL DEPENDENCY: Unsupported platform for [email protected]: wanted {"os":"darwin","arch":"any"} (current: {"os":"win32","arch":"x64"})

+ @angular/[email protected]
updated 1 package and audited 19503 packages in 33.58s
found 1 moderate severity vulnerability
  run `npm audit fix` to fix them, or `npm audit` for details

L:NetProjectBooksProjectBooksProjectClientApp>

Answer 1

i fixed my problem by adding :

<TypeScriptExperimentalDecorators>True</TypeScriptExperimentalDecorators> <TypeScriptEmitDecoratorMetadata>True</TypeScriptEmitDecora

this link might help u TypeScript error