google sign-in with angular2 and typescript - where to get gapi?

Question

I\'m trying to use google sign-in with angular2 by following this question: Google Sign-In for Websites and Angular 2 using Typescript

But I\'m getting an error:

Answer 1

I solved the issue by calling the following script in index.html

Note:

Use the following script without async defer:

and use async defer in this script