import { AssertionError } from "./assertion_error.ts";
export type AnyConstructor = new (...args: any[]) => any;export type GetConstructorType<T extends AnyConstructor> = T extends new (...args: any) => infer C ? C : never;
export function assertInstanceOf<T extends AnyConstructor>( actual: unknown, expectedType: T, msg = "",): asserts actual is GetConstructorType<T> { 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);}