title: angular-cli keeps throwing Error: Cannot find module 'source-map'
body: <p>So I installed the angular-cli using <code>npm install @angular-devkit/build-angular</code> but every time I try and use the <code>ng</code> command I get this error: <code>Error: Cannot find module 'source-map'</code> 
  even trying <code>ng version</code> throws the error.  I also trying installing it using <code>npm install angualt-cli</code> but that didnt work either.  Anyone know how to fix this issue?</p>