Improve performance of enframe #353

library(tibble)
options(digits = 3)

enframe2 <- function(x, name = "name", value = "value") {
  if (rlang::is_null(names(x))) {
    l <- list(seq_along(x), x)
  } else {
    l <- list(names(x), unname(x))
  }
  names(l) <- c(name, value)
  new_tibble(l)
}

x <- setNames(letters, letters)

microbenchmark::microbenchmark(
  enframe(x),
  enframe2(x)
)
#> Unit: microseconds
#>         expr    min     lq mean median     uq   max neval cld
#>   enframe(x) 1066.2 1116.9 1792 1185.7 1270.3 39110   100   b
#>  enframe2(x)   77.9   85.2  157   89.9   97.2  4283   100  a