Add custom error messages to specific errors in R

error-handler.R

# Add custom error messages to specific errors in R
error_handler <- function() {
  rlang::entrace()
  e <- rlang::last_error()$message
  if (grepl("there is no package called", x = e)) {
    message("* This can be a custom error message with multiple lines.")
  }
}

if ("rlang" %in% rownames(installed.packages())) {
  options(error = error_handler)
  options(rlang_backtrace_on_error = "none")
}

# Targeted errors
library("not.exist")

# Other errors
1 + "1"