feat: add js solution to lc problem: No.0260

Author: rain84

solution/0200-0299/0260.Single Number III/README.md

@@ -257,6 +257,25 @@ function singleNumber(nums: number[]): number[] {
 }
 ```
 
+#### JavaScript
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+function singleNumber(nums) {
+    const set = new Set();
+
+    for (const x of nums) {
+        if (set.has(x)) set.delete(x);
+        else set.add(x);
+    }
+
+    return [...set];
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0200-0299/0260.Single Number III/README_EN.md

@@ -255,6 +255,25 @@ function singleNumber(nums: number[]): number[] {
 }
 ```
 
+#### JavaScript
+
+```js
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+function singleNumber(nums) {
+    const set = new Set();
+
+    for (const x of nums) {
+        if (set.has(x)) set.delete(x);
+        else set.add(x);
+    }
+
+    return [...set];
+}
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0200-0299/0260.Single Number III/Solution2.js

@@ -0,0 +1,14 @@
+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+function singleNumber(nums) {
+    const set = new Set();
+
+    for (const x of nums) {
+        if (set.has(x)) set.delete(x);
+        else set.add(x);
+    }
+
+    return [...set];
+}