### Introduction

Consider this:

```
> const a = '{"__proto__":{ "b":5}}';
'{"__proto__":{ "b":5}}'

> const b = JSON.parse(a);
{ __proto__: { b: 5 } }

> b.b;
undefined

> const c = Object.assign({}, b);
{}

> c.b
5
```

The problem is that `JSON.parse()` retains the `__proto__` property as a plain object key. By
itself, this is not a security issue. However, as soon as that object is assigned to another or
iterated on and values copied, the `__proto__` property leaks and becomes the object's prototype.

### `Bourne.parse(text, [reviver], [options])`

Parses a given JSON-formatted text into an object where:

- `text` - the JSON text string.
- `reviver` - the `JSON.parse()` optional `reviver` argument.
- `options` - optional configuration object where:
    - `protoAction` - optional string with one of:
        - `'error'` - throw a `SyntaxError` when a `__proto__` key is found. This is the default value.
        - `'remove'` - deletes any `__proto__` keys from the result object.
        - `'ignore'` - skips all validation (same as calling `JSON.parse()` directly).

### `Bourne.scan(obj, [options])`

Scans a given object for prototype properties where:

- `obj` - the object being scanned.
- `options` - optional configuration object where:
    - `protoAction` - optional string with one of:
        - `'error'` - throw a `SyntaxError` when a `__proto__` key is found. This is the default value.
        - `'remove'` - deletes any `__proto__` keys from the input `obj`.

### `Bourne.safeParse(text, [reviver])`

Same as `Bourne.parse()` except that it returns `null` instead of throwing a `SyntaxError` when a `__proto__` key is found.