std/assert/assert_less.ts
2024-04-29 11:57:30 +09:00

25 lines
735 B
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
import { format } from "@std/internal/format";
import { AssertionError } from "./assertion_error.ts";
/**
* Make an assertion that `actual` is less than `expected`.
* If not then throw.
*
* @example
* ```ts
* import { assertLess } from "@std/assert/assert-less";
*
* assertLess(1, 2); // Doesn't throw
* assertLess(2, 1); // Throws
* ```
*/
export function assertLess<T>(actual: T, expected: T, msg?: string) {
if (actual < expected) return;
const actualString = format(actual);
const expectedString = format(expected);
throw new AssertionError(msg ?? `Expect ${actualString} < ${expectedString}`);
}