diff --git a/javascript/1_Two_Sum.js b/javascript/1_Two_Sum.js
new file mode 100644
index 000000000..af4a90494
--- /dev/null
+++ b/javascript/1_Two_Sum.js
@@ -0,0 +1,11 @@
+//Time: O(n)
+//Space: O(n)
+var twoSum = function(nums, target){
+    let visited = {};
+    for(let num in nums){
+        let desired = target - nums[num];
+        if(desired in visited)
+            return [num,visited[desired]];
+        visited[nums[num]] = num;
+    }return [];
+}
diff --git a/javascript/217-ContainsDuplicate.js b/javascript/217-ContainsDuplicate.js
new file mode 100644
index 000000000..1b6776f3b
--- /dev/null
+++ b/javascript/217-ContainsDuplicate.js
@@ -0,0 +1,11 @@
+// Time: O(n)
+// Space: O(n)
+
+var containsDuplicate = function(nums) {
+    let visited = {}; // visited object to account of number visited from the array nums
+    for(let num of nums){
+        if(num in visited) return true; //condition to check if object already has num
+        visited[num] = 1;
+    }
+    return false;
+}
diff --git a/javascript/242_Valid_Anagram.js b/javascript/242_Valid_Anagram.js
new file mode 100644
index 000000000..26adfac35
--- /dev/null
+++ b/javascript/242_Valid_Anagram.js
@@ -0,0 +1,18 @@
+//Time: O(s+t)
+//Space: O(s+t)
+var isAnagram = function(s, t) {
+    if(s.length !== t.length) return false;
+  
+    let visitedS = {}, visitedT = {};
+  
+    for(let num of s)
+        visitedS[num] = visitedS[num]+1 || 1;
+  
+    for(let num of t)
+        visitedT[num] = visitedT[num]+1 || 1;
+  
+    for(let keys in visitedS){
+        if(visitedS[keys] !== visitedT[keys]) return false;
+    }
+  return true;
+};
diff --git a/javascript/347_Top_K_Frequent_Elements.js b/javascript/347_Top_K_Frequent_Elements.js
new file mode 100644
index 000000000..43b3e94ab
--- /dev/null
+++ b/javascript/347_Top_K_Frequent_Elements.js
@@ -0,0 +1,20 @@
+//Time: O(nlogn)
+//Space: O(n)
+var topKFrequent = function(nums, k) {
+    let visited = {};
+    for(let num of nums)
+        visited[num] = visited[num]+1 || 1;
+    var sortable = [];
+    for (var vehicle in visited) {
+        sortable.push([vehicle, visited[vehicle]]);
+    }
+
+    sortable.sort(function(a, b) {
+        return  b[1]-a[1];
+    });
+    let res = [];
+    for(let i = 0; i<k;i++){
+        res.push(sortable[i][0]);
+    }
+    return res;
+};
diff --git a/javascript/49_Group_Anagrams.js b/javascript/49_Group_Anagrams.js
new file mode 100644
index 000000000..208b3df29
--- /dev/null
+++ b/javascript/49_Group_Anagrams.js
@@ -0,0 +1,15 @@
+//Time: O(nlogn)
+//Time: O(n)
+
+var groupAnagrams = function(strs) {
+    const sortedStr = strs.map(word => word.split("").sort().join(""));
+    const hash = {};
+    for(let str in strs){
+        if(!hash[sortedStr[str]]){
+            hash[sortedStr[str]] = [strs[str]];
+        }else{
+            hash[sortedStr[str]].push(strs[str]); 
+        }
+    }
+    return Object.values(hash);
+};