@@ -139,7 +139,7 @@ module.exports = {
 		 * @returns {string} capitalization state: "non-alpha", "lower", or "upper"
 		 */
 		function getCap(str) {
-			const firstChar = str.charAt(0);
+			const [firstChar] = str;
 
 			const firstCharLower = firstChar.toLowerCase();
 			const firstCharUpper = firstChar.toUpperCase();
 
@@ -29,6 +29,8 @@ ruleTester.run("new-cap", rule, {
 		"var x = new _;",
 		"var x = new $;",
 		"var x = new Σ;",
+		"var x = new 𐐀;",
+		"var x = 𐐨();",
 		"var x = new _x;",
 		"var x = new $x;",
 		"var x = new this;",
@@ -263,6 +265,54 @@ ruleTester.run("new-cap", rule, {
 				},
 			],
 		},
+		{
+			code: "var x = new 𐐨;",
+			errors: [
+				{
+					messageId: "lower",
+					line: 1,
+					column: 13,
+					endLine: 1,
+					endColumn: 15,
+				},
+			],
+		},
+		{
+			code: "var x = 𐐀();",
+			errors: [
+				{
+					messageId: "upper",
+					line: 1,
+					column: 9,
+					endLine: 1,
+					endColumn: 11,
+				},
+			],
+		},
+		{
+			code: "var x = new a.𐐨();",
+			errors: [
+				{
+					messageId: "lower",
+					line: 1,
+					column: 15,
+					endLine: 1,
+					endColumn: 17,
+				},
+			],
+		},
+		{
+			code: "var x = a.𐐀();",
+			errors: [
+				{
+					messageId: "upper",
+					line: 1,
+					column: 11,
+					endLine: 1,
+					endColumn: 13,
+				},
+			],
+		},
 		{
 			code: "var x = new a.b.c;",
 			errors: [