Password Grant generate token using HTTR package in R OAuth2 - r

Question

Brand new to API's and in a bit over my head. Reading a bit and searching around but still confused. I was given the following code to run in curl to generate a token using oauth2 with the password grant. I want to implement this code in R and running into some issues.
curl -H "Content-type: application/x-www-form-urlencoded" -H "Authorization: Basic xxxyyy123xxx==" -d "grant_type=password&username={username}&password={password}" https://{website}.com/rest/v2/oauth/token
When I run the above command in a terminal it generates a token which I have successfully used in R using this code:
token <- {character string generated by the above curl command}
call <- "https://{website}.com/rest/v2/services/APIService/getRegistryRecordByAccessionID?id={id#}"
df <- as.data.frame(fromJSON(content(httr::GET(call, add_headers(Authorization = paste("Bearer", token))), "text"), flatten = TRUE))
All I want is to generate the token in R instead of using another program like I have been. This is where my errors come up. The basic format I believe is:
token <- oauth2.0_token(endpoint = oauth_endpoint(
authorize = NULL,
access = "https://{website}.com/rest/v2/oauth/token"),
app = oauth_app(), #not sure how to set this up
use_basic_auth = T,
add_headers(Content-type = "application/x-www-form-urlencoded",
Authorization = "Basic xxxyyy123xxx==") #not sure if i need the authorization header here, I believe I need the content-type heder
)

Answer 1

From MrFlick's comments above, we can integrate the curl auhtorization commands into a POST using the httr package. We then look at the content of the object this returns which will include the access token in the first item in the list.
token <- content(httr::POST("https://{website}.com/rest/v2/oauth/token", body=list(grant_type="password", "username="{username}", password="{password}"), encode="form"))[[1]]