Merge pull request #285 from yjunechoe/docfix-snowball2df

Minor fixes for `snowball2df()`

R/oa2df.R

@@ -870,11 +870,6 @@ topics2df <- function(data, verbose = TRUE,
 
 #' Flatten snowball result
 #'
-#' |  id|title |...|cited_by_count| referenced_works   |cited_by |...|
-#' | 100|foo   |...|             1| 98, 99             |101      |...|
-#' | 200|bar   |...|             2| 198, 199           |201, 202 |...|
-#' | 300|wug   |...|             2| 296, 297, 298, 299 |301, 302 |...|
-#'
 #' @param data List result from `oa_snowball`.
 #' @param verbose Logical. If TRUE, print information on wrangling process.
 #'
@@ -948,5 +943,5 @@ snowball2df <- function(data, verbose = FALSE) {
   nodes_augmented$connection_count <-
     nodes_augmented$backward_count + nodes_augmented$forward_count
 
-  nodes_augmented
+  tibble::as_tibble(nodes_augmented)
 }