std/assert/exists.ts
Asher Gomez 5803cc9172
BREAKING(assert): remove assert from module names (#5176)
* BREAKING(assert): remove `assert` from module names

* work

* fix

* work

* work

* tweaks

* fix
2024-07-02 13:42:40 +10:00

32 lines
938 B
TypeScript

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
import { AssertionError } from "./assertion_error.ts";
/**
* Make an assertion that actual is not null or undefined.
* If not then throw.
*
* @example Usage
* ```ts no-eval
* import { assertExists } from "@std/assert";
*
* assertExists("something"); // Doesn't throw
* assertExists(undefined); // Throws
* ```
*
* @typeParam T The type of the actual value.
* @param actual The actual value to check.
* @param msg The optional message to include in the error if the assertion fails.
*/
export function assertExists<T>(
actual: T,
msg?: string,
): asserts actual is NonNullable<T> {
if (actual === undefined || actual === null) {
const msgSuffix = msg ? `: ${msg}` : ".";
msg =
`Expected actual: "${actual}" to not be null or undefined${msgSuffix}`;
throw new AssertionError(msg);
}
}