FileReader error : Cannot read property 'size' of undefined

Question

Good Day,

I have this code:

function loadFile() {
 var fileToLoad = document.getElementById("loadMe").files[0];
 var fileStart = 0;
 var fileEnd = fileToLoad.size - 1;
 var fileReader = new FileReader();
 fileReader.onload = function(fileLoadedEvent) {
    var textFromFileLoaded = fileLoadedEvent.target.result;
    var string = textFromFileLoaded.split('&');
    pleaseDoSomethingWithTheContentOfTheFile(textFromFileLoaded);
 };
fileReader.readAsText(fileToLoad, "UTF-8");
}

I have an error :

Uncaught TypeError: Cannot read property 'size' of undefined at loadFile

According to this post there is no index [0]... But when I remove that, I still have the same error. Is this something coming from this code, or does it look good ? Thanks in advance! :)

Why don't you first attempt to hardcode the value -- let's make sure the `filereader` code is working as expected. Always good to simplify the the problem and start from a working baseline. — Kevin Friedheim, Jul 18 '17 at 18:13
@avrilalejandro, what should I use if not the load function? — EricF, Jul 18 '17 at 18:14

score 1 · Answer 1 · answered Jul 18 '17 at 18:24

1

double check whether the file is selected before calling loadFile function.

also use below code checking the size

if (!fileToLoad) {
 alert('Pleae select file');
 return;
}

answered Jul 18 '17 at 18:24

Immanuel

167
1
8

Thank You, but I have an error `Uncaught TypeError: Failed to execute 'readAsText' on 'FileReader': parameter 1 is not of type 'Blob'.` ... I'm not sure it's a value added to the code. – EricF Jul 18 '17 at 18:31
what is the size of the file?, instead of using onload eventm try onloadend, this link [link](https://stackoverflow.com/questions/33923985/parameter-is-not-of-type-blob) might help.. – Immanuel Jul 18 '17 at 18:52

FileReader error : Cannot read property 'size' of undefined

1 Answers1