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, Sep 28 '16 at 06:53
can you give me code to do this with using event listener and how to check all files was read — murtaza sanjeliwala, Sep 28 '16 at 07:02
Possible duplicate of [FileReader API: how to read files synchronously](http://stackoverflow.com/questions/8850418/filereader-api-how-to-read-files-synchronously) — Frxstrem, Sep 28 '16 at 07:09
@Frxstrem I don't thing that this is duplicate for this. This link only half of question — xAqweRx, Sep 28 '16 at 07:16
@murtazasanjeliwala provide more JS and HTML code if you need example. — xAqweRx, Sep 28 '16 at 07:18

score 2 · Accepted Answer · answered Sep 28 '16 at 07:24

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 '16 at 07:24

xAqweRx

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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. – murtaza sanjeliwala Sep 28 '16 at 07:31
You can update this value on drop event. That's all. – xAqweRx Sep 28 '16 at 08:04

How to make FileReader Asyncronous without Using FileReaderSync in Javascript?

1 Answers1