# Custom Error

An application-specific error class extending JavaScript's Error class.

## What is **Custom Error** in JavaScript?

**Custom Error** — An application-specific error class extending JavaScript's Error class.

```javascript
class InvalidOrderError extends Error {
}
```

Level: Journeyman · [More JavaScript terms at this level](https://www.ask-codey.com/glossary/subjects/javascript/journeyman)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/custom-error