From 0dbd3b2133180e55e6b5abc4eabe1b78abfc5cac Mon Sep 17 00:00:00 2001
From: Project Nayuki <me@nayuki.io>
Date: Fri, 16 Sep 2022 23:28:56 +0000
Subject: [PATCH] Simplified Unicode string handling logic in TypeScript code
 thanks to ES6 features.

---
 typescript-javascript/qrcodegen-input-demo.ts | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/typescript-javascript/qrcodegen-input-demo.ts b/typescript-javascript/qrcodegen-input-demo.ts
index f433564..4758632 100644
--- a/typescript-javascript/qrcodegen-input-demo.ts
+++ b/typescript-javascript/qrcodegen-input-demo.ts
@@ -127,17 +127,11 @@ namespace app {
 		// Returns the number of Unicode code points in the given UTF-16 string.
 		function countUnicodeChars(str: string): number {
 			let result: number = 0;
-			for (let i = 0; i < str.length; i++, result++) {
-				const c: number = str.charCodeAt(i);
-				if (c < 0xD800 || c >= 0xE000)
-					continue;
-				else if (0xD800 <= c && c < 0xDC00 && i + 1 < str.length) {  // High surrogate
-					i++;
-					const d: number = str.charCodeAt(i);
-					if (0xDC00 <= d && d < 0xE000)  // Low surrogate
-						continue;
-				}
-				throw new RangeError("Invalid UTF-16 string");
+			for (const ch of str) {
+				const cc = ch.codePointAt(0) as number;
+				if (0xD800 <= cc && cc < 0xE000)
+					throw new RangeError("Invalid UTF-16 string");
+				result++;
 			}
 			return result;
 		}