Add TypeScript solution for finding duplicates

Added TypeScript implementation for finding duplicates in an array.

Author: yanglbme

solution/0400-0499/0442.Find All Duplicates in an Array/README_EN.md

@@ -133,6 +133,27 @@ func findDuplicates(nums []int) []int {
 }
 ```
 
+#### TypeScript
+
+```ts
+function findDuplicates(nums: number[]): number[] {
+    for (let i = 0; i < nums.length; i++) {
+        while (nums[i] !== nums[nums[i] - 1]) {
+            const temp = nums[i];
+            nums[i] = nums[temp - 1];
+            nums[temp - 1] = temp;
+        }
+    }
+    const ans: number[] = [];
+    for (let i = 0; i < nums.length; i++) {
+        if (nums[i] !== i + 1) {
+            ans.push(nums[i]);
+        }
+    }
+    return ans;
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->