AssertionError and AssertionResult classes.
## What is AssertionError?
Assertion Error is a module that contains two classes: `AssertionError`, which
is an instance of an `Error`, and `AssertionResult` which is not an instance of
Error.
These can be useful for returning from a function - if the function "succeeds"
return an `AssertionResult` and if the function fails return (or throw) an
`AssertionError`.
Both `AssertionError` and `AssertionResult` implement the `Result` interface:
```typescript
interface Result {
name: "AssertionError" | "AssertionResult";
ok: boolean;
toJSON(...args: unknown[]): Record;
}
```
So if a function returns `AssertionResult | AssertionError` it is easy to check
_which_ one is returned by checking either `.name` or `.ok`, or check
`instanceof Error`.
## Installation
### Node.js
`assertion-error` is available on [npm](http://npmjs.org).
```
$ npm install --save assertion-error
```
### Deno
`assertion_error` is available on
[Deno.land](https://deno.land/x/assertion_error)
```typescript
import {
AssertionError,
AssertionResult,
} from "https://deno.land/x/assertion_error@2.0.0/mod.ts";
```