Function assertIsError

assertIsError<E>(error, ErrorClass?, msgMatches?, msg?): asserts error is E
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.
Type Parameters
- E extends Error = Error
  The type of the error to assert.
Parameters
- error: unknown
  The error to assert.
- OptionalErrorClass: (new (...args: any[]) => E)
  The optional error class to assert.
  - - new (...args): E
    - Parameters
      Rest...args: any[]
      Returns E
- OptionalmsgMatches: string | RegExp
  The optional string or RegExp to assert in the error message.
- Optionalmsg: string
  The optional message to display if the assertion fails.
Returns asserts error is E
Example: Usage
```
import { assertIsError } from "@std/assert";

assertIsError(null); // Throws
assertIsError(new RangeError("Out of range")); // Doesn't throw
assertIsError(new RangeError("Out of range"), SyntaxError); // Throws
assertIsError(new RangeError("Out of range"), SyntaxError, "Out of range"); // Doesn't throw
assertIsError(new RangeError("Out of range"), SyntaxError, "Within range"); // Throws
```
- Defined in assert/is_error.ts:29