Sheets JavaScript API Uncaught Error

问题

I'm playing around with the new version of the Google Sheets API in my Aurelia application (I'm using TypeScript). I've managed to login the user and ask for the required scopes but when I'm trying to get the values of a spreadsheet the API throws the following error:

cb=gapi.loaded_0:269 Uncaught Error: arrayForEach was called with a non array value(…)

This is how I initialize the API and login the user:

gapi.load("auth2", () => {
    gapi.auth2.init({
       'client_id': this.clientId,
       'scope': this.scopes.join(' ')
    }).then(() => {
           this.auth = gapi.auth2.getAuthInstance();
           this.auth.signIn().then(response => {
               gapi.load("client", () => {
                     gapi.client.load("sheets", "v4", () => {
                         gapi.client.sheets.spreadsheets.values.get({
                             spreadsheetId: this.testSheet,
                             range: 'Class Data!A2:E'
                          }).then((response) => {console.log(response);});
                     });
               });
           })
    });
});

The scopes variable is an array of scopes:

scopes: string[] = ["https://www.googleapis.com/auth/spreadsheets.readonly", "https://www.googleapis.com/auth/spreadsheets", "https://www.googleapis.com/auth/drive.readonly", "https://www.googleapis.com/auth/drive"]

The user logs in successfully, I can even get their name and email. After loading the Sheets API I've checked `gapi.client' and the 'sheets' object is there but when I try to get data from a spreadsheet it fails with the above error. The example I'm running is against Google's public spreadsheet that is used in this example. Also note that there is nothing wrong with my client id as I've run Google's sample code with it and it works fine.