1var assert = require('assert');
2
3function isPalindrome(str) {
4  if (!str || str === '') {
5    return true;
6  } else {
7    let left = 0;
8    let right = str.length - 1;
9    let leftChar;
10    let rightChar;
11
12    while (left < right) {
13      leftChar = str.charAt(left).toLowerCase();
14      rightChar = str.charAt(right).toLowerCase();
15
16      if (isAlphaNumeric(leftChar) && isAlphaNumeric(rightChar)) {
17        if (leftChar == rightChar) {
18          left++;
19          right--;
20        } else {
21          return false;
22        }
23      } else {
24        if (!isAlphaNumeric(leftChar)) {
25          left++;
26        }
27        if (!isAlphaNumeric(rightChar)) {
28          right--;
29        }
30      }
31    }
32
33    return true;
34  }
35}
36
37function isAlphaNumeric(c) {
38  if (/[^a-zA-Z0-9]/.test(c)) {
39    return false;
40  } else {
41    return true;
42  }
43}
44
45console.log(isPalindrome('A Santa Lived As a Devil At NASA'));
46
47try {
48  assert.equal(isPalindrome('A Santa Lived As a Devil At NASA'), true);
49
50  console.log(
51    'PASSED: ' +
52      "assert.equal(isPalindrome('A Santa Lived As a Devil At NASA'),true)"
53  );
54} catch (err) {
55  console.log(err);
56}
57
58try {
59  assert.equal(isPalindrome('gold'), false);
60
61  console.log('PASSED: ' + "assert.equal(isPalindrome('gold'),false)");
62} catch (err) {
63  console.log(err);
64}
65
66try {
67  assert.equal(isPalindrome('a'), true);
68
69  console.log('PASSED: ' + "assert.equal(isPalindrome('a'),true)");
70} catch (err) {
71  console.log(err);
72}
73
74try {
75  assert.equal(isPalindrome('racecar'), true);
76
77  console.log('PASSED: ' + "assert.equal(isPalindrome('racecar'),true)");
78} catch (err) {
79  console.log(err);
80}