Add workaround for cordova FileReader

[vially]

As mentioned in several other places, cordova-plugin-file is overwriting the FileReader with one that doesn't follow the spec.

This is arguably a problem with cordova-plugin-file. But since a fix doesn't seem to be very high on their priority list, maybe adding this temporary workaround for it to pannellum would be a good short term solution.

[jineshmehta16]

Hi Can this solution be Implemented for normal Ionic framework where pannellum is not included?

I am facing this issue in my Ionic project, I have tried to reorder cordova and polyfill javascripts still it didn't solve the problem. In my project panaroma is not required. So how can I address in this situation?

[vially]

Can this solution be Implemented for normal Ionic framework where pannellum is not included?

This solution could not be implemented in Ionic because it would then break plugins which rely on the implementation of FileReader provided by the cordova-plugin-file plugin (e.g.: file-system access). The only place where this mess could be fixed properly would be in the cordova-plugin-file by either not overwriting the global FileReader object or at least overwrite it in a way that is 100% compatible with the spec.

In my project panaroma is not required. So how can I address in this situation?

Most probably you would have to patch the library that is using the FileReader API (most probably in a similar way to my patch here). But obviously that's not a good long-term solution because we can not expect that all the libraries that make use of the FileReader API implement a workaround just to be compatible with cordova-plugin-file.

[mpetroff]

A fix might be low on their priority list, but it's not on mine at all. Mobile / app frameworks are not officially supported; I just added a note to the README to make this policy explicit. While I'll accept pull requests that make minor tweaks to fix compatibility with these frameworks, I'm not adding any code that specifically targets one of them (like this pull request does).