From 01170ede653215bc0eae4932bec0d5d3c66d16f3 Mon Sep 17 00:00:00 2001
From: Sasha Koss <koss@nocorp.me>
Date: Wed, 13 Sep 2017 16:41:04 +0700
Subject: [PATCH] Treat null as an invalid date (closes #537)

---
 CHANGELOG.md        | 4 ++++
 src/isValid/test.js | 5 +++++
 src/toDate/index.js | 4 ++++
 src/toDate/test.js  | 6 ++++++
 4 files changed, 19 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 59b3638657..b2ea6e0277 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -366,6 +366,10 @@ for the list of changes made since `v2.0.0-alpha.1`.
 
 - **BREAKING**: The Bower & UMD/CDN package versions are no longer supported.
 
+- **BREAKING**: `null` now is not a valid date. `isValid(null)` returns `false`;
+  `toDate(null)` returns an invalid date. Since `toDate` is used internally
+  by all the functions, operations over `null` will also return an invalid date.
+
 ## [1.28.5] - 2017-05-19
 
 ### Fixed
diff --git a/src/isValid/test.js b/src/isValid/test.js
index 261c2049ad..40ed1aaea6 100644
--- a/src/isValid/test.js
+++ b/src/isValid/test.js
@@ -25,6 +25,11 @@ describe('isValid', function () {
     assert(isValid(NaN) === false)
   })
 
+  it('treats null as an invalid date', function () {
+    var result = isValid(null)
+    assert(result === false)
+  })
+
   it('throws `RangeError` if `options.additionalDigits` is not convertable to 0, 1, 2 or undefined', function () {
     // $ExpectedMistake
     var block = isValid.bind(null, new Date(), {additionalDigits: NaN})
diff --git a/src/toDate/index.js b/src/toDate/index.js
index c34a29253d..7dc505413e 100644
--- a/src/toDate/index.js
+++ b/src/toDate/index.js
@@ -82,6 +82,10 @@ export default function toDate (argument, dirtyOptions) {
     throw new TypeError('1 argument required, but only ' + arguments.length + ' present')
   }
 
+  if (argument === null) {
+    return new Date(NaN)
+  }
+
   var options = dirtyOptions || {}
 
   var additionalDigits = options.additionalDigits === undefined ? DEFAULT_ADDITIONAL_DIGITS : Number(options.additionalDigits)
diff --git a/src/toDate/test.js b/src/toDate/test.js
index 80120b8835..1d14a36495 100644
--- a/src/toDate/test.js
+++ b/src/toDate/test.js
@@ -247,6 +247,12 @@ describe('toDate', function () {
       assert(result instanceof Date)
       assert(isNaN(result))
     })
+
+    it('returns Invalid Date if argument is null', function () {
+      var result = toDate(null)
+      assert(result instanceof Date)
+      assert(isNaN(result))
+    })
   })
 
   it('implicitly converts options', function () {