Array types shouldn't have to be the same

[alexandrulesi]

Consider something like:

export interface DiffData<Ta, Tb> {
    removed: Ta[];
    added: Tb[];
}
export declare function diff<Ta, Tb>(a: Ta[], b: Tb[], compareFunc?: (ia: Ta, ib: Tb) => boolean): DiffData<Ta, Tb>;

My concrete use case is: I have some records in the db and new records coming in. The records in the db have ids, the new ones do not. I need the ids to know what records I want to archive in the db. Now I can't use this package without some workaround.

[YuJianrong]

WHy not just ignore id and compare the content in compareFunc?

[alexandrulesi]

I managed to get around it by making id optional on the type, but I have to follow it up with an assertion to get the original type back. It's a bit hacky but it does the job.