refactor: copy words before sorting

Author: azu

src/word-utils.js

@@ -1,6 +1,7 @@
 export function isAllCapitals(word) {
     return /^[A-Z]+$/.test(word);
 }
+
 /**
  * Capital Word to Acronym
  * @param {string} CapitalWord
@@ -23,26 +24,28 @@ export function expandOneWordToAcronym(CapitalWord) {
     }
     return acronym;
 }
+
 /*
  * create Acronym from words.
  * @param {string[]} words
- * @returns (1)string if only one word (2) array if multiple words
+ * @returns {string[]} string if only one word (2) array if multiple words
  */
 export function expandWordsToAcronym(words) {
     //XMLHttpRequest -> XHR
     if (words.length === 1) {
         return [expandOneWordToAcronym(words[0])];
     } else {
         const result = [];
-        //In American Broadcast Company -> ["C", "BC", "ABC", "IABC"]
-        words.reverse().reduce((acronym, word, i) => {
+        // In American Broadcast Company -> ["C", "BC", "ABC", "IABC"]
+        const reversedWords = words.slice().reverse();
+        reversedWords.reduce((acronym, word, i) => {
             acronym.unshift(word.charAt(0));
             result.push(acronym.join(""));
             return acronym;
         }, []);
 
-        //In American Broadcast Company -> ["I", "IA", "IAB", "IABC"]
-        words.reverse().reduce((acronym, word, i) => {
+        // In American Broadcast Company -> ["I", "IA", "IAB", "IABC"]
+        words.reduce((acronym, word, i) => {
             acronym.push(word.charAt(0));
             result.push(acronym.join(""));
             return acronym;