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@planet-a/affinity-node

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// Copyright 2018-2025 the Deno authors. MIT license. // This module is browser compatible. import { AssertionError } from "./assertion_error.js"; /** * Make an assertion that `obj` is an instance of `type`. * If not then throw. * * @example Usage * ```ts ignore * import { assertInstanceOf } from "@std/assert"; * * assertInstanceOf(new Date(), Date); // Doesn't throw * assertInstanceOf(new Date(), Number); // Throws * ``` * * @typeParam T The expected type of the object. * @param actual The object to check. * @param expectedType The expected class constructor. * @param msg The optional message to display if the assertion fails. */ export function assertInstanceOf(actual, expectedType, msg = "") { if (actual instanceof expectedType) return; const msgSuffix = msg ? `: ${msg}` : "."; const expectedTypeStr = expectedType.name; let actualTypeStr = ""; if (actual === null) { actualTypeStr = "null"; } else if (actual === undefined) { actualTypeStr = "undefined"; } else if (typeof actual === "object") { actualTypeStr = actual.constructor?.name ?? "Object"; } else { actualTypeStr = typeof actual; } if (expectedTypeStr === actualTypeStr) { msg = `Expected object to be an instance of "${expectedTypeStr}"${msgSuffix}`; } else if (actualTypeStr === "function") { msg = `Expected object to be an instance of "${expectedTypeStr}" but was not an instanced object${msgSuffix}`; } else { msg = `Expected object to be an instance of "${expectedTypeStr}" but was "${actualTypeStr}"${msgSuffix}`; } throw new AssertionError(msg); }