CSS: Trim whitespace surrounding CSS Custom Properties values

The spec has recently changed and CSS Custom Properties values are trimmed now.
This change makes jQuery polyfill that new behavior for all browsers.

Ref w3c/csswg-drafts#774
Fixes gh-4926
Closes gh-4930

8 files changed, 43 insertions, 13 deletions

diff --git a/src/css.js b/src/css.js
index c82a08c54..b50aa3d91 100644
--- a/src/css.js
+++ b/src/css.js
@@ -4,6 +4,7 @@ import nodeName from "./core/nodeName.js";
 import rcssNum from "./var/rcssNum.js";
 import isIE from "./var/isIE.js";
 import rnumnonpx from "./css/var/rnumnonpx.js";
+import rcustomProp from "./css/var/rcustomProp.js";
 import cssExpand from "./css/var/cssExpand.js";
 import isAutoPx from "./css/isAutoPx.js";
 import cssCamelCase from "./css/cssCamelCase.js";
@@ -24,7 +25,6 @@ var
 	// except "table", "table-cell", or "table-caption"
 	// See here for display values: https://developer.mozilla.org/en-US/docs/CSS/display
 	rdisplayswap = /^(none|table(?!-c[ea]).+)/,
-	rcustomProp = /^--/,
 	cssShow = { position: "absolute", visibility: "hidden", display: "block" },
 	cssNormalTransform = {
 		letterSpacing: "0",
diff --git a/src/css/curCSS.js b/src/css/curCSS.js
index 59a639f68..6d8b6a2d3 100644
--- a/src/css/curCSS.js
+++ b/src/css/curCSS.js
@@ -1,9 +1,12 @@
 import jQuery from "../core.js";
 import isAttached from "../core/isAttached.js";
 import getStyles from "./var/getStyles.js";
+import rcustomProp from "./var/rcustomProp.js";
+import rtrim from "../var/rtrim.js";
 
 function curCSS( elem, name, computed ) {
-	var ret;
+	var ret,
+		isCustomProp = rcustomProp.test( name );
 
 	computed = computed || getStyles( elem );
 
@@ -11,6 +14,11 @@ function curCSS( elem, name, computed ) {
 	if ( computed ) {
 		ret = computed.getPropertyValue( name ) || computed[ name ];
 
+		// trim whitespace for custom property (issue gh-4926)
+		if ( isCustomProp ) {
+			ret = ret.replace( rtrim, "$1" );
+		}
+
 		if ( ret === "" && !isAttached( elem ) ) {
 			ret = jQuery.style( elem, name );
 		}
diff --git a/src/css/var/rcustomProp.js b/src/css/var/rcustomProp.js
new file mode 100644
index 000000000..f435e7cd7
--- /dev/null
+++ b/src/css/var/rcustomProp.js
@@ -0,0 +1 @@
+export default ( /^--/ );
diff --git a/src/selector.js b/src/selector.js
index f7e8d9b60..4b9c8b6ed 100644
--- a/src/selector.js
+++ b/src/selector.js
@@ -5,8 +5,9 @@ import documentElement from "./var/documentElement.js";
 import indexOf from "./var/indexOf.js";
 import pop from "./var/pop.js";
 import push from "./var/push.js";
-import whitespace from "./selector/var/whitespace.js";
+import whitespace from "./var/whitespace.js";
 import rbuggyQSA from "./selector/rbuggyQSA.js";
+import rtrim from "./var/rtrim.js";
 import isIE from "./var/isIE.js";
 
 // The following utils are attached directly to the jQuery object.
@@ -71,7 +72,6 @@ var i,
 
 	// Leading and non-escaped trailing whitespace, capturing some non-whitespace characters preceding the latter
 	rwhitespace = new RegExp( whitespace + "+", "g" ),
-	rtrim = new RegExp( "^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$", "g" ),
 
 	rcomma = new RegExp( "^" + whitespace + "*," + whitespace + "*" ),
 	rcombinators = new RegExp( "^" + whitespace + "*([>+~]|" + whitespace + ")" +
diff --git a/src/selector/rbuggyQSA.js b/src/selector/rbuggyQSA.js
index 7a6210733..bae05398f 100644
--- a/src/selector/rbuggyQSA.js
+++ b/src/selector/rbuggyQSA.js
@@ -1,5 +1,5 @@
 import isIE from "../var/isIE.js";
-import whitespace from "./var/whitespace.js";
+import whitespace from "../var/whitespace.js";
 
 var rbuggyQSA = isIE && new RegExp(
 
diff --git a/src/var/rtrim.js b/src/var/rtrim.js
new file mode 100644
index 000000000..89d86d17a
--- /dev/null
+++ b/src/var/rtrim.js
@@ -0,0 +1,6 @@
+import whitespace from "./whitespace.js";
+
+export default new RegExp(
+	"^" + whitespace + "+|((?:^|[^\\\\])(?:\\\\.)*)" + whitespace + "+$",
+	"g"
+);
diff --git a/src/selector/var/whitespace.js b/src/var/whitespace.js
index dcac814c7..dcac814c7 100644
--- a/src/selector/var/whitespace.js
+++ b/src/var/whitespace.js
diff --git a/test/unit/css.js b/test/unit/css.js
index 8ade482ff..100b8c8c5 100644
--- a/test/unit/css.js
+++ b/test/unit/css.js
@@ -1738,9 +1738,16 @@ QUnit.testUnlessIE( "css(--customProperty)", function( assert ) {
 		"    .test__customProperties {\n" +
 		"        --prop1:val1;\n" +
 		"        --prop2: val2;\n" +
-		"        --prop3:val3 ;\n" +
-		"        --prop4:\"val4\";\n" +
-		"        --prop5:'val5';\n" +
+		"        --prop3:   val3;\n" +
+		"        --prop4:val4 ;\n" +
+		"        --prop5:val5   ;\n" +
+		"        --prop6: val6 ;\n" +
+		"        --prop7:   val7   ;\n" +
+		"        --prop8:\"val8\";\n" +
+		"        --prop9:'val9';\n" +
+		"        --prop10:\f\r\n\t val10 \f\r\n\t;\n" +
+		"        --prop11:\u000C\u000D\u000A\u0009\u0020val11\u0020\u0009\u000A\u000D\u000C;\n" +
+		"        --prop12:\u000Bval12\u000B;\n" +
 		"    }\n" +
 		"</style>"
 	);
@@ -1749,7 +1756,7 @@ QUnit.testUnlessIE( "css(--customProperty)", function( assert ) {
 		$elem = jQuery( "<div>" ).addClass( "test__customProperties" )
 			.appendTo( "#qunit-fixture" ),
 		webkitOrBlink = /\bsafari\b/i.test( navigator.userAgent ),
-		expected = 10;
+		expected = 17;
 
 	if ( webkitOrBlink ) {
 		expected -= 2;
@@ -1777,16 +1784,24 @@ QUnit.testUnlessIE( "css(--customProperty)", function( assert ) {
 
 	assert.equal( $elem.css( "--prop1" ), "val1", "Basic CSS custom property" );
 
-	assert.equal( $elem.css( "--prop2" ), " val2", "Preceding whitespace maintained" );
-	assert.equal( $elem.css( "--prop3" ), "val3 ", "Following whitespace maintained" );
+	assert.equal( $elem.css( "--prop2" ), "val2", "Preceding whitespace trimmed" );
+	assert.equal( $elem.css( "--prop3" ), "val3", "Multiple preceding whitespace trimmed" );
+	assert.equal( $elem.css( "--prop4" ), "val4", "Following whitespace trimmed" );
+	assert.equal( $elem.css( "--prop5" ), "val5", "Multiple Following whitespace trimmed" );
+	assert.equal( $elem.css( "--prop6" ), "val6", "Preceding and Following whitespace trimmed" );
+	assert.equal( $elem.css( "--prop7" ), "val7", "Multiple preceding and following whitespace trimmed" );
 
 	// Support: Chrome <=49 - 73+, Safari <=9.1 - 12.1+
 	// Chrome treats single quotes as double ones.
 	// Safari treats double quotes as single ones.
 	if ( !webkitOrBlink ) {
-		assert.equal( $elem.css( "--prop4" ), "\"val4\"", "Works with double quotes" );
-		assert.equal( $elem.css( "--prop5" ), "'val5'", "Works with single quotes" );
+		assert.equal( $elem.css( "--prop8" ), "\"val8\"", "Works with double quotes" );
+		assert.equal( $elem.css( "--prop9" ), "'val9'", "Works with single quotes" );
 	}
+
+	assert.equal( $elem.css( "--prop10" ), "val10", "Multiple preceding and following escaped unicode whitespace trimmed" );
+	assert.equal( $elem.css( "--prop11" ), "val11", "Multiple preceding and following unicode whitespace trimmed" );
+	assert.equal( $elem.css( "--prop12" ), "\u000Bval12\u000B", "Multiple preceding and following non-CSS whitespace reserved" );
 } );
 
 // IE doesn't support CSS variables.