import { ApolloLink } from 'apollo-link';
import { omit } from 'shared/omit';

/**
 * The "__typename" property added by Apollo Client causes errors when posting the entity
 * back in a mutation. Therefore this link will remove all such keys before the object
 * reaches the API layer.
 *
 * See: https://github.com/apollographql/apollo-client/issues/1913#issuecomment-393721604
 */
export class OmitTypenameLink extends ApolloLink {
    constructor() {
        super((operation, forward) => {
            if (operation.variables) {
                operation.variables = omit(operation.variables, ['__typename'], true);
            }

            return forward ? forward(operation) : null;
        });
    }
}
