Core: Improve regular expression comparisons

Use ES2015 `flags` when available.

Fixes gh-909
Closes gh-916

src/equiv.js

@@ -59,6 +59,10 @@ QUnit.equiv = (function() {
 		return false;
 	}
 
+	function getRegExpFlags( regexp ) {
+		return "flags" in regexp ? regexp.flags : regexp.toString().match( /[gimuy]*$/ )[ 0 ];
+	}
+
 	var callbacks = {
 		"string": useStrictEquality,
 		"boolean": useStrictEquality,
@@ -76,10 +80,7 @@ QUnit.equiv = (function() {
 			return a.source === b.source &&
 
 				// Include flags in the comparison
-				a.global === b.global &&
-				a.ignoreCase === b.ignoreCase &&
-				a.multiline === b.multiline &&
-				a.sticky === b.sticky;
+				getRegExpFlags( a ) === getRegExpFlags( b );
 		},
 
 		// - skip when the property is a method of an instance (OOP)

test/main/deepEqual.js

@@ -452,7 +452,7 @@ QUnit.test( "RegExp", function( assert ) {
 	// typeof a === "function";    // Oops, false in IE and Opera, true in FF and Safari ("object")
 
 	// Tests same regex with same modifiers in different order
-	var regex1, regex2, regex3, r3a, r3b,
+	var regex1, regex2, regex3, r3a, r3b, ru1, ru2,
 		r1 = /foo/,
 		r2 = /foo/gim,
 		r3 = /foo/gmi,
@@ -484,6 +484,20 @@ QUnit.test( "RegExp", function( assert ) {
 	assert.equal( QUnit.equiv( rm1, rg1 ), false, "Modifier" );
 	assert.equal( QUnit.equiv( rg1, rg2 ), true, "Modifier" );
 
+	// Compare unicode modifier
+	try {
+		r2 = new RegExp( "foo", "umig" );
+		r3 = new RegExp( "foo", "mgiu" );
+		assert.equal( QUnit.equiv( r2, r3 ), true, "Modifier order" );
+		assert.equal( QUnit.equiv( r1, r2 ), false, "Modifier" );
+
+		ru1 = new RegExp( "/u{1D306}", "u" );
+		ru2 = new RegExp( "/u{1D306}", "u" );
+		assert.equal( QUnit.equiv( ru1, rg1 ), false, "Modifier" );
+		assert.equal( QUnit.equiv( rg1, ru1 ), false, "Modifier" );
+		assert.equal( QUnit.equiv( ru1, ru2 ), true, "Modifier" );
+	} catch ( e ) {}
+
 	// Different regex, same modifiers
 	r1 = /[a-z]/gi;
 	r2 = /[0-9]/gi; // oops! different