Async code getting an undefined result

searchData.js

// final code for openweather.com app 
// **********************************

     searchData = async () => { 
        // API call
        let data = await fetch(link);
                                                            console.log('inside API');
        const res = await data.json();
        this.parseChecker(res);
    };
      
    parseChecker = async (res) => {
        if (res !== undefined) {
            this.updateFromServer(res);
        } else { console.log('error, data is undefined') }
    };

    updateFromServer = (res) => {
        let transitionObject = [...res.list]
        const updatedArray = transitionObject.filter(function(city) {
            return cities.indexOf(city);
          });
          
                                                            console.log(updatedArray);
    };

edit: issue i had

console.log(teste); // Response {type: "cors", url: "http://api.openweathermap.org/data/2.5/group?id=34…PID=200f283586f507e8c77b876afa998b97&units=metric", redirected: false, status: 200, ok: true, …}
const testeLista = teste.list

I'm trying to use testeLista as an object with the array 'list' on it. But it isn't. This is just the response from the server, not a json object