From 311373f82ee242bac25d7a1f0002481ff6f229ca Mon Sep 17 00:00:00 2001
From: Sergey Rubanov <chi187@gmail.com>
Date: Sun, 3 Nov 2019 21:27:56 +0300
Subject: [PATCH] Fix Math.signbit semantics

According [spec draft](https://tc39.es/proposal-Math.signbit/Math.signbit.html#spec), Math.signbit returns `true` only for negative values and `Math.signbit(NaN)` should return `true`
---
 .../core-js/modules/esnext.math.signbit.js    |  2 +-
 tests/commonjs.js                             |  2 +-
 tests/pure/esnext.math.signbit.js             | 20 +++++++++----------
 tests/tests/esnext.math.signbit.js            | 20 +++++++++----------
 4 files changed, 22 insertions(+), 22 deletions(-)

diff --git a/packages/core-js/modules/esnext.math.signbit.js b/packages/core-js/modules/esnext.math.signbit.js
index 0d8f4e82bc47..3ece8eae7578 100644
--- a/packages/core-js/modules/esnext.math.signbit.js
+++ b/packages/core-js/modules/esnext.math.signbit.js
@@ -4,6 +4,6 @@ var $ = require('../internals/export');
 // https://github.com/tc39/proposal-Math.signbit
 $({ target: 'Math', stat: true }, {
   signbit: function signbit(x) {
-    return (x = +x) != x ? x : x == 0 ? 1 / x == Infinity : x > 0;
+    return (x = +x) == x && x == 0 ? 1 / x == -Infinity : x < 0;
   }
 });
diff --git a/tests/commonjs.js b/tests/commonjs.js
index 09e376aad2e2..fe674182881a 100644
--- a/tests/commonjs.js
+++ b/tests/commonjs.js
@@ -143,7 +143,7 @@ for (const _PATH of ['../packages/core-js-pure', '../packages/core-js']) {
   ok(load('features/math/radians')(180) === Math.PI);
   ok(load('features/math/scale')(3, 1, 2, 1, 2) === 3);
   ok(load('features/math/umulh')(0xFFFFFFFF, 7) === 6);
-  ok(load('features/math/signbit')(-2) === false);
+  ok(load('features/math/signbit')(-2) === true);
   ok(typeof load('features/math/seeded-prng')({ seed: 42 }).next().value === 'number');
   ok(load('features/number/constructor')('5') === 5);
   ok(load('features/number/epsilon') === 2 ** -52);
diff --git a/tests/pure/esnext.math.signbit.js b/tests/pure/esnext.math.signbit.js
index 9e29c8e08580..4f0efa8a24b2 100644
--- a/tests/pure/esnext.math.signbit.js
+++ b/tests/pure/esnext.math.signbit.js
@@ -2,14 +2,14 @@ import signbit from 'core-js-pure/features/math/signbit';
 
 QUnit.test('Math.signbit', assert => {
   assert.isFunction(signbit);
-  assert.same(signbit(NaN), NaN);
-  assert.same(signbit(), NaN);
-  assert.same(signbit(-0), false);
-  assert.same(signbit(0), true);
-  assert.strictEqual(signbit(Infinity), true);
-  assert.strictEqual(signbit(-Infinity), false);
-  assert.strictEqual(signbit(13510798882111488), true);
-  assert.strictEqual(signbit(-13510798882111488), false);
-  assert.strictEqual(signbit(42.5), true);
-  assert.strictEqual(signbit(-42.5), false);
+  assert.strictEqual(signbit(NaN), false);
+  assert.strictEqual(signbit(), false);
+  assert.strictEqual(signbit(-0), true);
+  assert.strictEqual(signbit(0), false);
+  assert.strictEqual(signbit(Infinity), false);
+  assert.strictEqual(signbit(-Infinity), true);
+  assert.strictEqual(signbit(13510798882111488), false);
+  assert.strictEqual(signbit(-13510798882111488), true);
+  assert.strictEqual(signbit(42.5), false);
+  assert.strictEqual(signbit(-42.5), true);
 });
diff --git a/tests/tests/esnext.math.signbit.js b/tests/tests/esnext.math.signbit.js
index 60e913d3dbde..44ac0feeb10b 100644
--- a/tests/tests/esnext.math.signbit.js
+++ b/tests/tests/esnext.math.signbit.js
@@ -5,14 +5,14 @@ QUnit.test('Math.signbit', assert => {
   assert.arity(signbit, 1);
   assert.looksNative(signbit);
   assert.nonEnumerable(Math, 'signbit');
-  assert.same(signbit(NaN), NaN);
-  assert.same(signbit(), NaN);
-  assert.same(signbit(-0), false);
-  assert.same(signbit(0), true);
-  assert.strictEqual(signbit(Infinity), true);
-  assert.strictEqual(signbit(-Infinity), false);
-  assert.strictEqual(signbit(13510798882111488), true);
-  assert.strictEqual(signbit(-13510798882111488), false);
-  assert.strictEqual(signbit(42.5), true);
-  assert.strictEqual(signbit(-42.5), false);
+  assert.strictEqual(signbit(NaN), false);
+  assert.strictEqual(signbit(), false);
+  assert.strictEqual(signbit(-0), true);
+  assert.strictEqual(signbit(0), false);
+  assert.strictEqual(signbit(Infinity), false);
+  assert.strictEqual(signbit(-Infinity), true);
+  assert.strictEqual(signbit(13510798882111488), false);
+  assert.strictEqual(signbit(-13510798882111488), true);
+  assert.strictEqual(signbit(42.5), false);
+  assert.strictEqual(signbit(-42.5), true);
 });