`error-class-utils` is a tiny utility library for creating robust custom Error subclasses in JavaScript/TypeScript. It provides helpers to correctly set a non‑enumerable `name` property, polyfill the `error.cause` feature on older Node and browsers, and fix edge‑cases when the native `Error` constructor has been polyfilled—making custom errors behave consistently across environments. It’s aimed at library authors and developers who need reliable, standards‑compliant error classes.