How to make FileReader Asyncronous without Using FileReaderSync in Javascript?

Question

I am using FileReader for reading multiple files and folders through drag and drop in chrome using javascript. It is working properly, but problem is that i want to call function after all file and folder read completes. I can't because it is asyncronous operation and FileReaderSync is not supported in chrome. So is there any way to doing this?

this is my code,

entry.file(function (file) {

                        var reader = new FileReader();
                        reader.onloadend = function (e) {
                            data.push(this.result);

                        };

                        reader.readAsText(file);
                    });

As a tip: make an event listener where you can check whether all the files was read and do your trick. — xAqweRx
– xAqweRx, Commented Sep 28, 2016 at 6:53
can you give me code to do this with using event listener and how to check all files was read — murtaza sanjeliwala
– murtaza sanjeliwala, Commented Sep 28, 2016 at 7:02
Possible duplicate of FileReader API: how to read files synchronously — Freyja
– Freyja, Commented Sep 28, 2016 at 7:09
@Frxstrem I don't thing that this is duplicate for this. This link only half of question — xAqweRx
– xAqweRx, Commented Sep 28, 2016 at 7:16
@murtazasanjeliwala provide more JS and HTML code if you need example. — xAqweRx
– xAqweRx, Commented Sep 28, 2016 at 7:18

xAqweRx · Accepted Answer · 2016-09-28 07:24:02Z

2

As an example of what can be used here. This is can't be used as "Copy&Paste" variant :

var filesCount = "give here number of files";

var callbackFunction = function(){
    if(data.length == filesCount ){
        Console.log( "Assume this as the end of all files reading" );
    }
}
entry.file(function (file) {

    var reader = new FileReader();
    reader.onloadend = function (e) {
        data.push(this.result);
        callbackFunction();
    };

    reader.readAsText(file);
});

answered Sep 28, 2016 at 7:24

xAqweRx

1,2361 gold badge10 silver badges23 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

murtaza sanjeliwala Over a year ago

files count is not fixed because in drag and drop folder there can be many files and folders inside parent folder, this is the problem. if it is fix than i dont require to ask you.

xAqweRx Over a year ago

You can update this value on drop event. That's all.

Collectives™ on Stack Overflow

How to make FileReader Asyncronous without Using FileReaderSync in Javascript?

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related