Next page token R Google Places API

I am attempting to get restaurant details from the Google places API in R. I can successfully get the 20 results that Google provides however I realize that as it returns a next_page_token, then this means there are other results (which is logical is there are more than 20 restaurants around the 50km radius of the location I am searching). However when I use next_page_token it returns NULL. Here is my code:

install.packages("googleway")
library(googleway)

key <- 'my key'

df_places <- google_places(search_string = "restaurant", 
                       location = c(-33, 151),
                       page_token = "next_page_token",
                       radius = 50000,
                       key = key)
df_places$results$name
df_places$results$rating
df_places$results$formatted_address
df_places$results$geometry$location

And here is what it returns without next_page_token:

 [1] "Gennaro's Italian Restaurant"                   
 [2] "Mount Broke Wines & Restaurant"                 
 [3] "Oak Dairy Bar"                                  
 [4] "Bimbadgen"                                      
 [5] "Subway Restaurant"                              
 [6] "Muse Restaurant"                                
 [7] "Ocean Restaurant"

etc...

Here is what it returns with next_page_token:

> df_places$results$name
NULL

Just wondering what I am doing wrong to repeatedly return NULL?

Solution

First thing to check, are you using the quoted string "next_page_token", or an object next_page_token that you get from the result to the first query to google_places()

Here's a working example of your code

library(googleway)

key <- 'api_key'

df_places <- google_places(search_string = "restaurant", 
                           location = c(-33, 151),
                           radius = 50000,
                           key = key)

token <- df_places$next_page_token

df_next_places <- google_places(search_string = "restaurant", 
                           location = c(-33, 151),
                           page_token = token,
                           radius = 50000,
                           key = key)

df_places$results$name[1:5]
# [1] "Gennaro's Italian Restaurant"   "Mount Broke Wines & Restaurant"
# [3] "Oak Dairy Bar"                  "Bimbadgen"                     
# [5] "Subway Restaurant"

df_next_places$results$name[1:5]
# [1] "RidgeView Restaurant"          "Emerson's Cafe and Restaurant"
# [3] "EXP. Restaurant"               "Margan Restaurant & Winery"   
# [5] "AL-Oi Thai Restaurant"