Let's try mozilla's fixedCharAt function

commands/drawDesign.cjs

@@ -217,7 +217,7 @@ function charIterate(input) {
 	let temp = input.split('');
 	for (let i = 0; i < stringLength; ++i) {
 		let compareString = temp.join("");
-		if (surrogatePairs.exec(input).index == i) {
+		if (surrogatePairs.exec(compareString).index == i) {
 			stringLength--;
 			console.log("Decreasing stringLength variable to", stringLength);
 		}