const handleRepoDelete = (collectionId, repoId) => {
    const newCollections = collections.map(
        (collection) => {
            // assign collection.id, collection.repos
            const {
                id,
                repos
            } = collection
            // if if is !== collectionId
            // do noting with this
            if (id !== collectionId) {
                return collection
            }
            // if the collection id
            // is equal to id to delete
            // return repos that id are different 
            // from the id to delete

            // this returns the new collection object
            // but how this works?
            return {
                ...collection,
                repos: repos.filter(
                    ({ id }) => {
                        id !== repoId
                    }
                )
            }
        }
    )
    console.log(newCollections);
}