feat: add javascript solution to lc problem: No.1812.Determine Color … (doocs#408)

Author: zhaocchen

solution/1800-1899/1812.Determine Color of a Chessboard Square/README.md

@@ -82,6 +82,20 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} coordinates
+ * @return {boolean}
+ */
+ var squareIsWhite = function(coordinates) {
+    let x = coordinates.charAt(0).charCodeAt() - 'a'.charCodeAt() + 1;
+    let y = Number(coordinates.charAt(1));
+    return ((x + y) & 1) == 1;
+};
+```
+
 ### **...**
 
 ```

solution/1800-1899/1812.Determine Color of a Chessboard Square/README_EN.md

@@ -72,6 +72,20 @@ class Solution {
 }
 ```
 
+### **JavaScript**
+
+```js
+/**
+ * @param {string} coordinates
+ * @return {boolean}
+ */
+ var squareIsWhite = function(coordinates) {
+    let x = coordinates.charAt(0).charCodeAt() - 'a'.charCodeAt() + 1;
+    let y = Number(coordinates.charAt(1));
+    return ((x + y) & 1) == 1;
+};
+```
+
 ### **...**
 
 ```

solution/1800-1899/1812.Determine Color of a Chessboard Square/Solution.js

@@ -0,0 +1,9 @@
+/**
+ * @param {string} coordinates
+ * @return {boolean}
+ */
+ var squareIsWhite = function(coordinates) {
+    let x = coordinates.charAt(0).charCodeAt() - 'a'.charCodeAt() + 1;
+    let y = Number(coordinates.charAt(1));
+    return ((x + y) & 1) == 1;
+};