cordova-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Vladimir Kotikov (JIRA)" <>
Subject [jira] [Reopened] (CB-12085) FileReader#readAsArrayBuffer reads whole file
Date Mon, 26 Jun 2017 10:53:00 GMT


Vladimir Kotikov reopened CB-12085:
      Assignee:     (was: Nikita Matrosov)

Reopening as it's probably still an issue

> FileReader#readAsArrayBuffer reads whole file
> ---------------------------------------------
>                 Key: CB-12085
>                 URL:
>             Project: Apache Cordova
>          Issue Type: Bug
>          Components: cordova-plugin-file
>    Affects Versions: 4.3.0
>         Environment: Android
>            Reporter: Damian Senn
>            Priority: Critical
>              Labels: performance
> Reading a File with
> ```js
> let fr = new FileReader
> fr.onload = () => done(fs.result)
> fr.readAsArrayBuffer(blob)
> ```
> Is very slow, I'm assuming this is because it reads the whole file, then transfers this
via base64 to the JS world, where it is converted to an ArrayBuffer. My use-case involves
reading some media metadata in JS-World, this usually involves reading several bytes (maybe
around 100b to 1kb) of 2mb to 50mb files.
> I noticed this by profiling via Chrome-DevTools where the most time is being spent in
the `atob` function in `cordova/base64.toArrayBuffer`.
> So parsing some hundreds of bytes on a 3mb file may take around 3 to 4 seconds on my
Samsung Galaxy S4 and around 1 second on my Samsung Galaxy S6. (This is without trying to
read the actual metadata from the file).
> My guess is that this also has a very negative impact on memory usage and garbage collection.

This message was sent by Atlassian JIRA

To unsubscribe, e-mail:
For additional commands, e-mail:

View raw message