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Support - JavaScript & React Editor

Help, troubleshooting, and contact details for JavaScript & React Editor.

Published by Cosmovex

Frequently Asked Questions

How do I write and run a JavaScript program?

From the home screen tap New JS, write your code in the editor, then tap the Run button (play icon). Console output appears in the panel below the editor. Your code runs entirely on your device — no internet connection is required.

How do I preview a React component?

Tap New React on the home screen, write a function App() component using JSX, and tap Run. The live preview renders below the editor. The component you define is mounted automatically — you don't need to call ReactDOM.createRoot unless you want custom control.

Does React preview work offline?

Yes. The React runtime and the JSX transpiler are bundled inside the app, so the preview works without any internet connection. Go ahead and use it on a flight or in a tunnel.

How do I add CSS to my React preview?

Tap the Edit CSS icon in the top-right of the preview pane. Styles you write there are applied to your preview instantly.

What file types can I open?

Only .js and .jsx files are supported today..js opens in JavaScript mode,.jsx opens in React mode — the extension dictates the mode.

How do I save my code?

Open the overflow menu (three dots in the top-right of the editor) and choose Save as to save inside the app, or Save to device to export the file anywhere on your device — Downloads, a cloud sync folder, SD card, etc. React code saves as .jsx, JavaScript saves as .js.

How do I use the Examples?

The home screen shows a curated Examples grid with tabs for All / JS / React. Tap any card to open that example in the editor, then modify and run.

Why does the app show ads?

Ads help support continued development. You can remove all ads with a one-time Pro upgrade from Settings.

The app is crashing. What do I do?

Try closing and reopening the app. Make sure you have the latest version from Google Play. If a specific program causes the crash, check for infinite loops or very large memory usage. Email us with your device model, OS version, app version, and steps to reproduce.

Contact Support

For help, bug reports, or privacy-related questions, email trionapps@gmail.com. We usually respond within 24-48 hours.

Report a Bug

If something is not working as expected, include these details in your email:

  • Your device model and Android OS version
  • Your app version (found in Settings > About)
  • What you were trying to do
  • The error or unexpected result
  • Steps to reproduce the issue, if known

Important Links

App Information

  • App Name: JavaScript & React Editor
  • Package: com.cosmovex.jsvedit
  • Platform: Android
  • Developer: Cosmovex
  • Contact: trionapps@gmail.com