There can be several reasons why you may be getting the Javascript error on Discord. There has been reported cases about Discord app being blocked from launching by certain security software. If Discord was previously working but then stopped due to this error, it’s possible that your security software may be to blame. In some cases, this error may also prevent Discord from starting up. One of the annoying errors that many users may encounter in the course of their Discord usage is the “A fatal Javascript error occured.” This error usually indicates that Discord has stopped working because it’s missing an important set of files, particularly relating to Javascript. We now have Discord running properly on Steam Deck in game mode.Are you having an issue using Discord every time it returns a Javascript error? In this troubleshooting guide, we’ll show you how this issue is easily resolved. Also, the Web Browser controller layout seems to work best with Discord. I couldn't get the mouse cursor to appear. Also, a side note: You navigate Discover Overlay using the touchscreen. To use the tool, you'll want to have both Discord and Discover Overlay running in the background.

Under Launch Options, you want to replace whatever is written there with the following line of code: DISPLAY=:0 %command% run io._overlay. Right-click it, and then choose Properties. Go to your Steam library and look for Discover Overlay. Open up desktop Steam, go to Library, and at the bottom left corner, click on the plus sign, then Add a Non-Steam Game.

Now, we need to add both programs, Discord and Discover Overlay to Steam.

For this, go back to Discover, and search for Discover Overlay.

Next, we want to install one additional tweak to run the voice overlay.

(If the keyboard doesn't pop up, click the Steam Button + the X-button.) Install the app. You find it by clicking on the menu button.

In the desktop mode, open up Discover.

Click the Steam button, go down to Power, and then Switch to Desktop.

On your Steam Deck, go to desktop mode.

This is where this guide has you covered. But a few steps and one additional tool are needed for it correctly.

Thankfully, installing Discord on the Steam Deck is super easy, barely an inconvenience.

If you use your Steam Deck for multiplayer games with your friends, there is a high chance you'll want to use Discord to talk to your friends (and foes?).

Discord install