From 990f1d72aeb4ad9ab37679998699e53c66df3e52 Mon Sep 17 00:00:00 2001
From: Goran Peshanski <gpeshans@hfour.com>
Date: Fri, 10 Jan 2020 18:54:24 +0100
Subject: [PATCH] Added num.isNumberType and repourposed num.isNaN

---
 packages/toi/index.spec.ts | 11 +++++++++--
 packages/toi/index.ts      | 14 +++++++++++++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/packages/toi/index.spec.ts b/packages/toi/index.spec.ts
index 4024a80..dac19b7 100644
--- a/packages/toi/index.spec.ts
+++ b/packages/toi/index.spec.ts
@@ -219,13 +219,20 @@ describe("toi", () => {
       });
     });
 
-    describe("isNaN", () => {
-      assert(toi.num.isNaN(), {
+    describe("isNumberType", () => {
+      assert(toi.num.isNumberType(), {
         positive: [0, 1, -1, NaN],
         negative: [false, "", "-1", "0", "1", {}, [], new Number(0)]
       });
     });
 
+    describe("isNaN", () => {
+      assert(toi.num.isNaN(), {
+        positive: [NaN],
+        negative: [0, 1, -1, 0.1, -0.1, false, "", "-1", "0", "1", {}, [], new Number(0)]
+      });
+    });
+
     describe("isInteger", () => {
       assert(toi.num.isInteger(), {
         positive: [0, 0.0, -0.0, 1.0, -1.0, 1.0, -1.0, 1, -1],
diff --git a/packages/toi/index.ts b/packages/toi/index.ts
index c61ef12..2c06f26 100644
--- a/packages/toi/index.ts
+++ b/packages/toi/index.ts
@@ -331,12 +331,24 @@ export namespace num {
   /**
    * Check that the value is a `number` including `NaN`.
    */
-  export const isNaN = <X>() =>
+  export const isNumberType = <X>() =>
     wrap(
       "num.isNaN",
       allow<X, number>(value => "number" === typeof value, "value is not a number type")
     );
 
+  /**
+   * Check that the value is `NaN`.
+   */
+  export const isNaN = <X>() =>
+    wrap(
+      "num.isNaN",
+      allow<X, number>(
+        value => "number" === typeof value && Number.isNaN(value),
+        "value is not NaN"
+      )
+    );
+
   /**
    * Check that the value is an integer.
    */