Data: avoid using delete on DOM nodes

jbedard · jbedard · commit 5452c92c0d75 · 2015-08-16T13:13:12.000-07:00
diff --git a/src/data/Data.js b/src/data/Data.js
@@ -147,7 +147,11 @@ Data.prototype = {
 
 		// Remove the expando if there's no more data
 		if ( key === undefined || jQuery.isEmptyObject( cache ) ) {
-			delete owner[ this.expando ];
+			// Support: Chrome <=35 - 45
+			// Webkit & Blink performance suffers when deleting properties
+			// from DOM nodes, so set to undefined instead
+			// https://code.google.com/p/chromium/issues/detail?id=378607
+			owner[ this.expando ] = undefined;
 		}
 	},
 	hasData: function( owner ) {
diff --git a/src/manipulation.js b/src/manipulation.js
@@ -283,10 +283,14 @@ jQuery.extend({
 							}
 						}
 					}
-					delete elem[ dataPriv.expando ];
+					// Support: Chrome <=35 - 45
+					// Assign undefined instead of using delete, see Data#remove
+					elem[ dataPriv.expando ] = undefined;
 				}
 				if ( elem[ dataUser.expando ] ) {
-					delete elem[ dataUser.expando ];
+					// Support: Chrome <=35 - 45
+					// Assign undefined instead of using delete, see Data#remove
+					elem[ dataUser.expando ] = undefined;
 				}
 			}
 		}
diff --git a/test/unit/data.js b/test/unit/data.js
@@ -859,7 +859,7 @@ testIframeWithCallback( "enumerate data attrs on body (#14894)", "data/dataAttrs
 });
 
 test( "Check that the expando is removed when there's no more data", function() {
-	expect( 1 );
+	expect( 2 );
 
 	var key,
 		div = jQuery( "<div/>" );
@@ -870,7 +870,7 @@ test( "Check that the expando is removed when there's no more data", function()
 	// Make sure the expando is gone
 	for ( key in div[ 0 ] ) {
 		if ( /^jQuery/.test( key ) ) {
-			ok( false, "Expando was not removed when there was no more data" );
+			strictEqual( div[ 0 ][ key ], undefined, "Expando was not removed when there was no more data" );
 		}
 	}
 });
diff --git a/test/unit/manipulation.js b/test/unit/manipulation.js
@@ -2089,7 +2089,7 @@ test( "jQuery.cleanData eliminates all private data (gh-2127)", function() {
 });
 
 test( "jQuery.cleanData eliminates all public data", function() {
-	expect( 2 );
+	expect( 3 );
 
 	var key,
 		div = jQuery( "<div/>" );
@@ -2103,7 +2103,7 @@ test( "jQuery.cleanData eliminates all public data", function() {
 	// Make sure the expando is gone
 	for ( key in div[ 0 ] ) {
 		if ( /^jQuery/.test( key ) ) {
-			ok( false, "Expando was not removed when there was no more data" );
+			strictEqual( div[ 0 ][ key ], undefined, "Expando was not removed when there was no more data" );
 		}
 	}
 });

Original file line number	Diff line number	Diff line change
`@@ -283,10 +283,14 @@ jQuery.extend({`
`283`	`283`	`}`
`284`	`284`	`}`
`285`	`285`	`}`
`286`		`- delete elem[ dataPriv.expando ];`
	`286`	`+ // Support: Chrome <=35 - 45`
	`287`	`+ // Assign undefined instead of using delete, see Data#remove`
	`288`	`+ elem[ dataPriv.expando ] = undefined;`
`287`	`289`	`}`
`288`	`290`	`if ( elem[ dataUser.expando ] ) {`
`289`		`- delete elem[ dataUser.expando ];`
	`291`	`+ // Support: Chrome <=35 - 45`
	`292`	`+ // Assign undefined instead of using delete, see Data#remove`
	`293`	`+ elem[ dataUser.expando ] = undefined;`
`290`	`294`	`}`
`291`	`295`	`}`
`292`	`296`	`}`