express-server/express-api-server/email/main.js
/**
 * Create an OAuth2 client with the given credentials, and then execute the
 * given callback function.
 * @param {Object} credentials The authorization client credentials.
 * @param {function} callback The callback to call with the authorized client.
 */
Create an OAuth2 client with the given credentials, and then execute the
given callback function.
@param {Object} credentials The authorization client credentials.
@param {function} callback The callback to call with the authorized client.
Create an OAuth2 client with the given credentials and then execute the given callback function . @param { Object } credentials The authorization client credentials . @param { function } callback The callback to call with the authorized client .
function authorize(credentials, callback, user_data) {
    const {client_secret, client_id, redirect_uris} = credentials.installed;
    const oAuth2Client = new google.auth.OAuth2(
        client_id, client_secret, redirect_uris[0]);
    fileSystem.readFile(TOKEN_PATH, (err, token) => {
        if (err) return getNewToken(oAuth2Client, callback, user_data);
        oAuth2Client.setCredentials(JSON.parse(token));
        callback(oAuth2Client, user_data);
    });
}
function authorize ( credentials , callback , user_data ) { const { client_secret , client_id , redirect_uris } = credentials . installed ; const oAuth2Client = new google . auth . OAuth2 ( client_id , client_secret , redirect_uris [ 0 ] ) ; fileSystem . readFile ( TOKEN_PATH , ( err , token ) => { if ( err ) return getNewToken ( oAuth2Client , callback , user_data ) ; oAuth2Client . setCredentials ( JSON . parse ( token ) ) ; callback ( oAuth2Client , user_data ) ; } ) ; }
Create an OAuth2 client with the given credentials, and then execute the
 given callback function.
Create an OAuth2 client with the given credentials and then execute the given callback function .
// Check if we have previously stored a token.