"TypeError: Cannot freeze" when dispatching an action with payload of type FileList

[quynhethereal]

Hi everyone 👋

When I dispatch an action with payload of type FileList, ngrx would throw an error. Here is the sample code:

// myFile is of type FileList
this.store.dispatch(uploadActions.addFiles ( props: { documents:  myFile }));

This issue is resolved when I clone myFile, like this:

const cloneMyFile = [...myFile]

I'm looking to understand more about this behavior. There is a similar SO answer: https://stackoverflow.com/a/53092520 but I don't quite understand the explanation. They say that "FileList is a primitive data type so JS will treat it as read-only so it cannot be frozen" but I have tested in the JS console and JS is able to freeze this type (by calling Object.freeze). Moreover, I have tested dispatching actions with other primitive data types like Integer and the store works well.

I have searched the docs but don't seem to find relevant discussions about FileList data type. I have just started with ngrx so I might be missing sth obvious. Hopefully sb can provide me with pointers, cheers :)