I expect some of the code above can throw exceptions, in particular `uploadChunk()`, and in this case the handle will remain open. So probably should use something like a try/catch/finally block and close the handle in `finally` (and re-throw errors in the catch block)

Please make a copy of the options if you are going to modify them: `options = Object.assign({}, options)`

Please move this method directly in OneDriveApi as it is useful only there.

I think these two properties are not necessary as you can derive this info from the path (if it contains "createUploadSession", it needs `uploadBigFile()`. And ideally the file size should be retrieved where it's needed, directly in `uploadBigFile()`.

`===`

Please set it as `4*1024*1024`

Please set it as `7.5 * 1024 * 1024` for clarity

Please use strict equality `===`

Same, you don't need to create a new method, you can simply use the existing `stat()` method.

Please use the `stat()` method for this, and you can then get the size in the `size` property. As the code in this file needs to be duplicated for each platform, we try to keep it as lean as possible.