diff --git a/Sprint-1/JavaScript/calculateSumAndProduct/calculateSumAndProduct.js b/Sprint-1/JavaScript/calculateSumAndProduct/calculateSumAndProduct.js
index ce738c3..6598c9f 100644
--- a/Sprint-1/JavaScript/calculateSumAndProduct/calculateSumAndProduct.js
+++ b/Sprint-1/JavaScript/calculateSumAndProduct/calculateSumAndProduct.js
@@ -18,13 +18,12 @@
  */
 export function calculateSumAndProduct(numbers) {
   let sum = 0;
-  for (const num of numbers) {
-    sum += num;
-  }
-
   let product = 1;
+
   for (const num of numbers) {
     product *= num;
+    sum += num;
+
   }
 
   return {
@@ -32,3 +31,7 @@ export function calculateSumAndProduct(numbers) {
     product: product,
   };
 }
+
+// The function has 2 loops, one for the sum and the other for the product.
+// we actually don't need to loop twice, we can do both in a single loop.
+// the time complexity now is 0(n) and the space complexity is O(1).
\ No newline at end of file
diff --git a/Sprint-1/JavaScript/findCommonItems/findCommonItems.js b/Sprint-1/JavaScript/findCommonItems/findCommonItems.js
index 5619ae5..6524d17 100644
--- a/Sprint-1/JavaScript/findCommonItems/findCommonItems.js
+++ b/Sprint-1/JavaScript/findCommonItems/findCommonItems.js
@@ -12,3 +12,5 @@
 export const findCommonItems = (firstArray, secondArray) => [
   ...new Set(firstArray.filter((item) => secondArray.includes(item))),
 ];
+
+// the function does not need to be optimized as it is already efficient.
\ No newline at end of file
diff --git a/Sprint-1/JavaScript/hasPairWithSum/hasPairWithSum.js b/Sprint-1/JavaScript/hasPairWithSum/hasPairWithSum.js
index dd2901f..9ecc6c1 100644
--- a/Sprint-1/JavaScript/hasPairWithSum/hasPairWithSum.js
+++ b/Sprint-1/JavaScript/hasPairWithSum/hasPairWithSum.js
@@ -19,3 +19,6 @@ export function hasPairWithSum(numbers, target) {
   }
   return false;
 }
+
+// in this function, we need to use 2 loops to check if there is a pair of numbers that sum to the value.
+// nothing can be optimized in this function, it is already efficient.
\ No newline at end of file
diff --git a/Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs b/Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs
index dc5f771..38af872 100644
--- a/Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs
+++ b/Sprint-1/JavaScript/removeDuplicates/removeDuplicates.mjs
@@ -1,36 +1,23 @@
 /**
  * Remove duplicate values from a sequence, preserving the order of the first occurrence of each value.
  *
- * Time Complexity:
- * Space Complexity:
- * Optimal Time Complexity:
+ * Time Complexity: O(n)
+ * Space Complexity: O(n)
+ * Optimal Time Complexity: O(n)
  *
- * @param {Array} inputSequence - Sequence to remove duplicates from
+ * @param {Array} items - Sequence to remove duplicates from
  * @returns {Array} New sequence with duplicates removed
  */
 export function removeDuplicates(inputSequence) {
-  const uniqueItems = [];
+	const seen = new Set();
+    const uniqueItems = [];
 
-  for (
-    let currentIndex = 0;
-    currentIndex < inputSequence.length;
-    currentIndex++
-  ) {
-    let isDuplicate = false;
-    for (
-      let compareIndex = 0;
-      compareIndex < uniqueItems.length;
-      compareIndex++
-    ) {
-      if (inputSequence[currentIndex] === uniqueItems[compareIndex]) {
-        isDuplicate = true;
-        break;
-      }
-    }
-    if (!isDuplicate) {
-      uniqueItems.push(inputSequence[currentIndex]);
-    }
-  }
+    for (const value of inputSequence) {
+        if (!seen.has(value)) {
+            seen.add(value);
+            uniqueItems.push(value);
+        }
+	}
 
-  return uniqueItems;
-}
+    return uniqueItems;
+}
\ No newline at end of file