Refactor substitution logic in substituteCipherText function

main.js

@@ -77,15 +77,11 @@ function countTrigrams(str) {
 }
 
 function substituteCipherText(cipherText, substitutionMap) {
-	let substitutedText = '';
 	substitutionMap = constructMapFromInput(substitutionMap);
-	for (let i = 0; i < cipherText.length; i++) {
-		const letter = cipherText[i];
-		if (substitutionMap.has(letter)) {
-			substitutedText += substitutionMap.get(letter);
-		} else {
-			substitutedText += letter;
-		}
+	let substitutedText = cipherText;
+	for (let [key, value] of substitutionMap) {
+		let regex = new RegExp(key, "g"); //global regex meaning it will replace all matching string, not just the first one
+		substitutedText = substitutedText.replace(regex, value);
 	}
 	console.log(substitutedText);
 	return substitutedText;