AngularJS Error: npm ERR Unexpected end of JSON input while parsing near ...rms

Hi  All

I am new to angular , I want to Add the Datetime Control

inAngular ,  i import the package  like below

import {MatInputModule, MatCardModule, MdInputModule} from '@angular/material';
import {MatDatepickerModule} from '@angular/material/datepicker';

it is not finding the material ,

so when i Add npm install --save @angula/material

it is giving Error like

npm ERR! JSON.parse Unexpected token / in JSON at position 439 while parsing near '...rms": "~7.1.0",