// Copyright 2018-2025 the Deno authors. 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 Usage
* ```ts ignore
* import { assertLess } from "@std/assert";
*
* assertLess(1, 2); // Doesn't throw
* assertLess(2, 1); // Throws
* ```
*
* @typeParam T The type of the values to compare.
* @param actual The actual value to compare.
* @param expected The expected value to compare.
* @param msg The optional message to display if the assertion fails.
*/
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}`);
}
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