Add check if app is running in third- or first-party environment

Tried embedding excalidraw inside an frame and file loading and saving started throwing an error in Chrome but works on firefox.

Failed to execute 'showOpenFilePicker' on 'Window': Cross origin sub frames aren't allowed to show a file picker.

On further inspection, it looks like the underlying error is because of using showOpenFilePicker being used by this library.

Tried to repro on codesandbox here - https://codesandbox.io/s/exciting-hertz-jzjeg?file=/src/index.js (works on firefox but not on chrome)

[Pet3ris]

Thanks @apnerve, was able to reproduce and now integrated directories/files fully in the app 😃.

@tomayac nothing wrong with it whatsoever, just when I see a simple example not working in CodeSandbox that’s usually a good prompt to improve my understanding of a dependency, so I start there first.

Thanks both for your help!

[apnerve]

Yeah the Excalidraw example works well across all browsers for me, very weird that the CodeBrowser example doesn’t work at all. I tried to click on the window as instructed but that just serves to trigger the respective errors unfortunately.

I’m planning to use the library for an app so wanted to just have a minimal reproducible example of how to use it and what the return values look like, may have to just start building the functionality directly.

In case you meant the example I added in the issue, it doesn’t take into account the click and hence doesn’t work. Have bumped the version to ^0.16.0 and added a click handler and it works fine