diff --git a/typescript/0303-range-sum-query-immutable.ts b/typescript/0303-range-sum-query-immutable.ts
index e2d9c2efd..757a620a6 100644
--- a/typescript/0303-range-sum-query-immutable.ts
+++ b/typescript/0303-range-sum-query-immutable.ts
@@ -1,5 +1,5 @@
 class NumArray {
-
+  
     prefixSums: number[] = [];
 
     constructor(nums: number[]) {
diff --git a/typescript/0705-design-hashset.ts b/typescript/0705-design-hashset.ts
new file mode 100644
index 000000000..b1f3816cc
--- /dev/null
+++ b/typescript/0705-design-hashset.ts
@@ -0,0 +1,65 @@
+class _ListNode { // ListNode has a confict
+    key: number;
+    next: _ListNode | undefined;
+
+    constructor(key: number) {
+        this.key = key;
+    }
+}
+
+class MyHashSet {
+    readonly ARRAY_LENGTH = Math.pow(10, 4);
+    set = new Array<_ListNode>(this.ARRAY_LENGTH);
+
+    constructor() {
+        for (let i = 0; i < this.ARRAY_LENGTH; i++)
+            this.set[i] = new _ListNode(0);
+    }
+
+    add(key: number): void {
+        let cur = this.set[key % this.set.length];
+        
+        while (cur.next) {
+            if (cur.next.key === key)
+                return;
+
+            cur = cur.next;
+        }
+
+        cur.next = new _ListNode(key);
+    }
+
+    remove(key: number): void {
+        let cur = this.set[key % this.set.length];
+        
+        while (cur.next) {
+            if (cur.next.key === key) {
+                cur.next = cur.next.next;
+                return;
+            }
+
+            cur = cur.next;
+        }
+    }
+
+    contains(key: number): boolean {
+        let cur = this.set[key % this.set.length];
+        
+        while (cur.next) {
+            if (cur.next.key === key)
+                return true;
+
+            cur = cur.next;
+        }
+
+        return false;
+    }
+}
+
+/**
+ * Your MyHashSet object will be instantiated and called as such:
+ * var obj = new MyHashSet()
+ * obj.add(key)
+ * obj.remove(key)
+ * var param_3 = obj.contains(key)
+ */