How to find location of package?

Question

I am building an R package (let's call it "pkg"), and would like to write a function that downloads a file from the internet and saves it in the "inst/extdata" directory in my package's directory.

 download_file <- function(link) { 
     path <- ... # path to where "pkg" is stored
                 # something along the lines of ....../pkg
     download.file(link, paste(path, "inst/extdata", "newfile", sep = ""))
 }

Could you please help me get the "path"? While developing the package, I can just do "getwd()" -- however, when a user calls my package, her working directory might not be the pkg directory. In which case, how do I get the path to my package's directory?

Solution

Just run .libPaths() and it will show you the filepath to your library folder. Inside the library folder you can see all your packages.