std/assert/assert_false.ts
Lino Le Van c46143f0ac
chore: update copyright year (#4046)
* chore: update copyright year

* fix

---------

Co-authored-by: Asher Gomez <ashersaupingomez@gmail.com>
2024-01-02 08:11:32 +11:00

23 lines
659 B
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
import { AssertionError } from "./assertion_error.ts";
/** Assertion condition for {@linkcode assertFalse}. */
export type Falsy = false | 0 | 0n | "" | null | undefined;
/**
* Make an assertion, error will be thrown if `expr` have truthy value.
*
* @example
* ```ts
* import { assertFalse } from "https://deno.land/std@$STD_VERSION/assert/assert_false.ts";
*
* assertFalse(false); // Doesn't throw
* assertFalse(true); // Throws
* ```
*/
export function assertFalse(expr: unknown, msg = ""): asserts expr is Falsy {
if (expr) {
throw new AssertionError(msg);
}
}