Cannot find module '@angular/compiler'

I just run npm install and then ok.

Try to delete that "angular/cli": "1.0.0-beta.28.3", in the devDependencies it is useless , and add instead of it "@angular/compiler-cli": "^2.3.1", (since it is the current version, else add it by npm i --save-dev @angular/compiler-cli ), then in your root app folder run those commands:

1. rm -r node_modules (or delete your node_modules folder manually)
2. npm cache clean (npm > v5 add --force so: npm cache clean --force)
3. npm install