How to get data from a different channel youtube api node.js

I started using YouTube's API today since I want to make a Discord bot that can display a YouTube channels data. So, I went to the guides on the YouTube API site, followed the node.js guide, but ran into a problem. I do not know how I can get the data from a different channel than Google Developers (which is the channel their pulling data from in the explanation).

function getChannel(auth) {    var service = google.youtube('v3');    service.channels.list({      auth: auth,      part: 'snippet,contentDetails,statistics',      forUsername: 'GoogleDevelopers'    }, function(err, response) {      if (err) {        console.log('The API returned an error: '+ err);        return;      }      var channels = response.data.items;      if (channels.length == 0) {        console.log('No channel found.');      } else {        console.log('This channel\'s ID is %s. Its title is \'%s\', and '+'it has %s views.',                    channels[0].id,                    channels[0].snippet.title,                    channels[0].statistics.viewCount);      }    });  }

Above is the code they use. I expected I could change Google Developers to any other YouTube channel and it would return the data from that, but if I change it to, for example Fireship, I get the error below. I searched their API reference, but I don't really understand what I'm doing wrong.

if (channels.length == 0) {                   ^TypeError: Cannot read properties of undefined (reading 'length')

What should I do to fix this issue?

Thanks in advance!