Update 7-reverse-integer.js

Author: everthis

7-reverse-integer.js

@@ -1,3 +1,25 @@
+/**
+ * @param {number} x
+ * @return {number}
+ */
+const reverse = function (x) {
+  let res = 0, tail, newResult
+  const low = -Math.pow(2, 31), high = Math.pow(2, 31)
+  while(x !== 0) {
+    tail = x % 10
+    newResult = res * 10 + tail
+    // if((newResult - tail) / 10 !== res) return 0
+    if(newResult < low || newResult >= high) return 0
+    res = newResult
+    x = ~~(x / 10)
+  }
+  
+  return res
+};
+
+// another
+
+
 /**
  * @param {number} x
  * @return {number}