Revert "Core: make isNumeric limited to strings and numbers"

This reverts commit 15ac848868e993dfe5ccd7751a94f5c8edc288bc.

2 files changed, 7 insertions, 7 deletions

diff --git a/src/core.js b/src/core.js
index e8f0d9d37..f27306587 100644
--- a/src/core.js
+++ b/src/core.js
@@ -214,12 +214,12 @@ jQuery.extend( {
 
 	isNumeric: function( obj ) {
 
-		// As of jQuery 3.0, isNumeric is limited to
-		// strings and numbers (primitives or objects)
-		// that can be coerced to finite numbers (gh-2662)
-		var type = jQuery.type( obj );
-		return ( type === "number" || type === "string" ) &&
-			( obj - parseFloat( obj ) + 1 ) >= 0;
+		// parseFloat NaNs numeric-cast false positives (null|true|false|"")
+		// ...but misinterprets leading-number strings, particularly hex literals ("0x...")
+		// subtraction forces infinities to NaN
+		// adding 1 corrects loss of precision from parseFloat (#15100)
+		var realStringObj = obj && obj.toString();
+		return !jQuery.isArray( obj ) && ( realStringObj - parseFloat( realStringObj ) + 1 ) >= 0;
 	},
 
 	isPlainObject: function( obj ) {
diff --git a/test/unit/core.js b/test/unit/core.js
index 6aa2a3d63..dc083de31 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -455,8 +455,8 @@ QUnit.test( "isNumeric", function( assert ) {
 	assert.ok( t( 1.5999999999999999 ), "Very precise floating point number" );
 	assert.ok( t( 8e5 ), "Exponential notation" );
 	assert.ok( t( "123e-2" ), "Exponential notation string" );
+	assert.ok( t( new ToString( "42" ) ), "Custom .toString returning number" );
 
-	assert.equal( t( new ToString( "42" ) ), false, "Custom .toString returning number" );
 	assert.equal( t( "" ), false, "Empty string" );
 	assert.equal( t( "        " ), false, "Whitespace characters string" );
 	assert.equal( t( "\t\t" ), false, "Tab characters string" );