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std/assert/assert_is_error.ts

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// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.import { AssertionError } from "./assertion_error.ts";import { stripColor } from "../fmt/colors.ts";
/** * Make an assertion that `error` is an `Error`. * If not then an error will be thrown. * An error class and a string that should be included in the * error message can also be asserted. */export function assertIsError<E extends Error = Error>( error: unknown, // deno-lint-ignore no-explicit-any ErrorClass?: new (...args: any[]) => E, msgIncludes?: string, msg?: string,): asserts error is E { const msgSuffix = msg ? `: ${msg}` : "."; if (error instanceof Error === false) { throw new AssertionError( `Expected "error" to be an Error object${msgSuffix}}`, ); } if (ErrorClass && !(error instanceof ErrorClass)) { msg = `Expected error to be instance of "${ErrorClass.name}", but was "${ typeof error === "object" ? error?.constructor?.name : "[not an object]" }"${msgSuffix}`; throw new AssertionError(msg); } if ( msgIncludes && (!(error instanceof Error) || !stripColor(error.message).includes(stripColor(msgIncludes))) ) { msg = `Expected error message to include ${ JSON.stringify(msgIncludes) }, but got ${ error instanceof Error ? JSON.stringify(error.message) : '"[not an Error]"' // TODO(kt3k): show more useful information }${msgSuffix}`; throw new AssertionError(msg); }}