Javascript: Filereader onloadend with TypeError

ionic-v1
1

Actually I tried to read a file in ionic 2 using a filereader object.
But instead of firing the onloadend function I can see all my wanted
data in the console by adding the whole reader into the output, but I’m
not able to get this data.

Here’s my code:

loadFile(path) {
    this.platform.ready().then(() => {
        window.resolveLocalFileSystemURL(path, gotFile, fail);

        function fail() {
            // errorHandling
        }

        fileEntry.file(function(file) {
            var reader = new FileReader();

            reader.onloadend = function(evt) {
                console.log('onload');
            }

            reader.readAsText(file);     

            console.log(reader);

        })
    }
});

In the console I can see under onloadend inside the caller object under arguments and under caller the following message:

Exception: TypeError: 'caller' and 'arguments' are restricted function properties and cannot be accessed in this context. at Function.remoteFunction (:3:14) at Object.InjectedScript.callFunctionOn (:724:66)

How can I fix this problem? Thanks in advance!