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