This version is running inside a container and is therefore not able to access SDKs on your host system!
To execute commands on the host system, run WebStorm with:
$ flatpak run --talk-name=org.freedesktop.Flatpak com.jetbrains.WebStorm
And this inside the sandbox:
$ flatpak-spawn --host <COMMAND>
This allows applications to launch arbitrary commands on the host. This must not be used unless absolutely necessary and when no existing solutions using Flatpak or portals exist. This is are considered a security issue, use at your risk.
To make it permanent
$ flatpak override --user < --talk-name=org.freedesktop.Flatpak com.jetbrains.WebStorm
To make the Integrated Terminal automatically use the host system's shell,
you can modify Settings > Tools > Terminal > Shell path to
/usr/bin/env -- flatpak-spawn --host bash
This flatpak provides a standard development environment (gcc, python, etc). To see what's available:
$ flatpak run --command=sh com.jetbrains.WebStorm
$ ls /usr/bin (shared runtime)
$ ls /app/bin (bundled with this flatpak)
To get support for Node.js, you have to install SDK extension
$ flatpak install flathub org.freedesktop.Sdk.Extension.node24