SharePoint Get REST data with Fetch (with logging function)

SP-REST-Fetch

const getRestData = endpoint =>
    fetch(`${_spPageContextInfo.webAbsoluteUrl}/_api/web/${endpoint}`, 
    { credentials: "include", headers: { "accept": "application/json;odata=verbose" } })
        .then(res => res.json().then(data => { 
            return data.d.hasOwnProperty("results") ? data.d.results : data.d }))
        .catch(err => console.log(err));

const getListItems = listTitle => { return getRestData(`lists/getbytitle('${listTitle}')/items`) };

const logProps = (endpoint, prop) =>
    getRestData(endpoint).then(d => { 
    let log = str => console.log(str); 
        if (prop) if (d.length) for (i in d) log(d[i][prop])
        else log(d[prop])
        else log(d);
    });