assert_null: Assert that the input is NULL

In assertions: Simple Assertions for Beautiful and Customisable Error Messages

Assert that the input is NULL

Description

This function asserts that the input is NULL and aborts with an error message if it is not.

Usage

assert_null(x, msg = NULL, call = rlang::caller_env(), arg_name = NULL)

Arguments

x	A value to check.
msg	A character string containing the error message to display if x is not NULL.
call	Only relevant when pooling assertions into multi-assertion helper functions. See cli_abort for details.
arg_name	Advanced use only. Name of the argument passed (default: NULL, will automatically extract arg_name).

Value

invisible(TRUE) if x is NULL, otherwise aborts with the error message specified by msg.

Examples

assert_null(NULL)  # Passes

try({
 assert_null(1)  # Throws default error
 assert_null(1, msg = "Custom error message")  # Throws custom error
})

assertions documentation built on April 3, 2025, 5:52 p.m.