angular migrating from 7 to 9 code example
Example 1: ng update @angular/core @angular/cli
npm uninstall -g angular-cli
npm install -g @angular/cli@latest
Example 2: angular 8 to 9
First, update to the latest version of 8
ng update @angular/cli@8 @angular/core@8
Then, update to 9
ng update @angular/cli @angular/core