Get documents created by current user with SharePoint Online Search REST API

I need to get the modified/created document of the user currently logged into SharePoint Online using rest api. I am able to get all created documents, however, I am missing the logic to retrieve the currently user logged in and add it to the rest query. My code:

<script type="text/javascript" src="https://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.9.1.min.js"></script>
<div id="mydocuments"></div>
<script type="text/javascript">
var startrow = '&startrow=0'
var rowlimit = '&rowlimit=3'

var userName = "";

var searchQuery = _spPageContextInfo.webAbsoluteUrl + "/_api/search/query?&sourceid='e7ec8cee-ded8-43c9-beb5-436b54b31e84'" + "&refinementfilters='displayauthor:equals(\"" + userName + "\")'"

$.ajax({
    url: searchQuery,
    method: 'GET',
    headers: {
        'Accept': 'application/json; odata=verbose'
    },
    success: onQuerySuccess,
    error: onQueryFail
});

function onQuerySuccess(data) {
    var items = [];

    items.push("<span id='cardtitle'>" + 'My documents ' + "</span>");
    if (data.d.query.PrimaryQueryResult.RelevantResults.Table.Rows.results.length == 0) {
        items.push("<p>" + 'No results were found' + "</p>");
    } else {
        $(data.d.query.PrimaryQueryResult.RelevantResults.Table.Rows.results).each(function() {
            var path = keyValue(this, 'Path');
            var title = keyValue(this, 'Title');
            items.push('<li id="' + 'listContent' + '">' + '<img src="/_layouts/15/images/icdocx.png" class="projects" />' + ' <a href="' + path + '">' + title + '</a>' + '</li>');
        });

        items.push("</ul>");
        $("#mydocuments").html(items.join(''));
    }
}

function keyValue(row, fldName) {
    var ret = null;
    $.each(row.Cells.results, function() {
        if (this.Key == fldName) {
            ret = this.Value;
        }
    });
    return ret;
}

function onQueryFail(sender, args) {
    alert('Query failed. Error:' + args.get_message());
}

</script>

So currently I am unable to figure out how to add the Current user name to this code.

There is a property userDisplayName in _spPageContextInfo, unfortunately it's not documented (wiki/docs). Some folks have noticed the changes: Updates to _spPageContextInfo

So:

userName = _spPageContextInfo.userDisplayName