From 791befe2d799cc5fa5954d5df768d7348e523a23 Mon Sep 17 00:00:00 2001
From: Lucas Vieira <vieiralucas@users.noreply.github.com>
Date: Wed, 14 Sep 2016 22:34:39 -0300
Subject: [PATCH] Add toJSON to proxyExcludedKeys

Hello there,

While I was working on #799, I discovered that you cannot call `JSON.stringify` on an assertion because o proxify.

```javascript
const { expect } = require('chai');

const equal = expect(1).to.equal(1);
JSON.stringify(equal); // This will throw Error: Invalid Chai property: toJSON
``
---
 lib/chai/config.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/chai/config.js b/lib/chai/config.js
index 9c8be3cff..ca1e30a79 100644
--- a/lib/chai/config.js
+++ b/lib/chai/config.js
@@ -90,5 +90,5 @@ module.exports = {
    * @api public
    */
 
-  proxyExcludedKeys: ['then', 'inspect']
+  proxyExcludedKeys: ['then', 'inspect', 'toJSON']
 };