feat: Added reverse-integer js

reverse-integer/js/index.js

@@ -0,0 +1,57 @@
+/*
+Given a 32-bit signed integer, reverse digits of an integer.
+
+Example 1:
+
+Input: 123
+Output: 321
+Example 2:
+
+Input: -123
+Output: -321
+Example 3:
+
+Input: 120
+Output: 21
+Note:
+Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. For the purpose of this problem, assume that your function returns 0 when the reversed integer overflows.
+*/
+
+/**
+ * @param {number} x
+ * @return {number}
+ */
+const reverse = function(x) {
+  const MAX_INT = Math.pow(2,31) -1;
+  const MIN_INT = Math.pow(2,31)* -1;
+
+  const X = x.toString();
+  
+  const isNeg = X[0] === '-';
+  let reverseIntegerString = X.split('').reverse().join('');
+
+  const reverseInteger = isNeg ? parseInt(reverseIntegerString) * -1 : parseInt(reverseIntegerString);
+
+  return (reverseInteger >= MAX_INT || reverseInteger <= MIN_INT) ?  0 :  reverseInteger;
+};
+
+/* Test Case 1
+ * Input:  123
+ * Output: 321
+ */
+x = 123;
+console.log(reverse(x));
+
+/* Test Case 2
+ * Input: -123
+ * Output: -321
+ */
+x = -123;
+console.log(reverse(x));
+
+/* Test Case 3
+ * Input: 120
+ * Output: 21
+ */
+x = 120;
+console.log(reverse(x));