Save R JSON object with new lines for each record

Question

I\'m trying to save a JSON object where each line is a record. How can I save the JSON object so that the number of lines is equal to the number of records (5 in example below)

Answer 1

jsonlite::stream_out will only work for flat data.frame objects:

jsonlite::stream_out (list (iris, mtcars)) # error!

More complex structures can be written with intact line breaks simply using writeLines:

x <- jsonlite::toJSON (list (iris, mtcars), pretty = TRUE)
con <- file ("tmp.json")
writeLines (x, con)
close (con)

jsonlite::fromJSON will read this straight back.