options(encoding="UTF-8")
library(httr)
# use rjstat JSON-stat library
library(rjstat)
# Adress to the very small readymade JSON-Stat dataset for Retail Sales Index 
url <- "http://data.ssb.no/api/v0/dataset/1066.json?lang=en"
d.tmp<-GET(url)
# get content from d.tmp as text, using fromJSONstat
sbtable <- fromJSONstat(content(d.tmp, "text"))
# get only datasett from sbtable
ds <- sbtable[[1]]
# Show dataset
ds
# Barplot of the boring type
barplot(ds$value, names.arg = ds$`time`)

# ======
# Same using the R-package PxWebApiData and the url above
library(PxWebApiData)
ApiData1(url, getDataByGET = TRUE)