while adding angular material error shows index,d.ts code example

Example 1: @angular/material/index.d.ts

It is changed in updated version of angular i think.
To resolve this issue you need to downgrade the angular/material version

Try to update the angular material (@angular/material@7.3.2) of this version.

npm uninstall -g @angular/material
npm cache clean --force

npm install -g @angular/material@7

Example 2: File "..node_modules/@angular/material/index.d.ts' is not a module.ts(2306)

#import the individual modules, as Angular no longer support installeting from @angular/material