D3 Examples - // source http://jsbin.com/nurixetuzi

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<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JS Bin</title>
</head>
<body>
​
<script id="jsbin-javascript">
var test1 = 'ana';
var test2 = 'abba';
var test3 = 'abbz';
var test4 = 'annad';
var test5 = 'I';
var test6 = '';
var test7 = 'max exam';
var test8 = 'aNna';
var test9 = 'Avid diva';
​
//helper functions
var reverse = function(word) {
  var arr = [];
  for (var i = 0; i < word.length; i++) {
    arr[i] = word[word.length - 1 - i];
    arr[word.length - 1 - i] = word[i];
  }
  return arr.join('');
};
​
var removeSpaces = function(word) {
  var spaceRemoved = [];
  for (var j = 0; j < word.length; j ++) {
    if (word[j] != ' ') {
      spaceRemoved.push(word[j]);
    } 
  }
  return spaceRemoved.join('');
};
​
var isPalindrome = function(phrase) {
  var cleanPhrase = removeSpaces(phrase).toLowerCase();
  //console.log(cleanPhrase);
  var result = false;
  if (cleanPhrase.length === 0) {
    console.log('Please enter a word or phrase');
  } else if (cleanPhrase.length === 1) {
    result = true;
  } else if (cleanPhrase.length % 2 === 0) {
    //console.log(cleanPhrase.slice(0, phrase.length / 2));
    //console.log(cleanPhrase.slice(phrase.length / 2));
    //console.log(reverse(cleanPhrase.slice(phrase.length / 2)));
    if (cleanPhrase.slice(0, cleanPhrase.length / 2) == reverse(cleanPhrase.slice(cleanPhrase.length / 2))) {
      result = true;
    }
  } else { //odd number of characters
    //console.log(cleanPhrase.slice(0, Math.floor(cleanPhrase.length / 2)));
    //console.log(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2)));
    //console.log(reverse(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2))));    
    if (cleanPhrase.slice(0, Math.floor(cleanPhrase.length / 2)) == reverse(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2)))) {
      result = true;
    }
  }  
  if (result) {
    console.log(phrase + ' is a palindrome');
  } else {
    console.log(phrase + ' is not a palindrome');    
  }
};
​
//testing helper function
//console.log(removeSpaces(' abc jk'));
//console.log(removeSpaces('ab cjk '));
​
//main tests
isPalindrome(test1);
isPalindrome(test2);
isPalindrome(test3);
isPalindrome(test4);
​
//edge cases
isPalindrome(test5);
isPalindrome(test6);
​
//testing input with spaces
isPalindrome(test7);
​
//testing input with upper case and lower case chars
isPalindrome(test8);
isPalindrome(test9);
​
/* resources used
https://www.palindromelist.net/
*/
</script>
​
​
​
<script id="jsbin-source-javascript" type="text/javascript">var test1 = 'ana';
var test2 = 'abba';
var test3 = 'abbz';
var test4 = 'annad';
var test5 = 'I';
var test6 = '';
var test7 = 'max exam';
var test8 = 'aNna';
var test9 = 'Avid diva';
​
//helper functions
var reverse = function(word) {
  var arr = [];
  for (var i = 0; i < word.length; i++) {
    arr[i] = word[word.length - 1 - i];
    arr[word.length - 1 - i] = word[i];
  }
  return arr.join('');
};
​
var removeSpaces = function(word) {
  var spaceRemoved = [];
  for (var j = 0; j < word.length; j ++) {
    if (word[j] != ' ') {
      spaceRemoved.push(word[j]);
    } 
  }
  return spaceRemoved.join('');
};
​
var isPalindrome = function(phrase) {
  var cleanPhrase = removeSpaces(phrase).toLowerCase();
  //console.log(cleanPhrase);
  var result = false;
  if (cleanPhrase.length === 0) {
    console.log('Please enter a word or phrase');
  } else if (cleanPhrase.length === 1) {
    result = true;
  } else if (cleanPhrase.length % 2 === 0) {
    //console.log(cleanPhrase.slice(0, phrase.length / 2));
    //console.log(cleanPhrase.slice(phrase.length / 2));
    //console.log(reverse(cleanPhrase.slice(phrase.length / 2)));
    if (cleanPhrase.slice(0, cleanPhrase.length / 2) == reverse(cleanPhrase.slice(cleanPhrase.length / 2))) {
      result = true;
    }
  } else { //odd number of characters
    //console.log(cleanPhrase.slice(0, Math.floor(cleanPhrase.length / 2)));
    //console.log(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2)));
    //console.log(reverse(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2))));    
    if (cleanPhrase.slice(0, Math.floor(cleanPhrase.length / 2)) == reverse(cleanPhrase.slice(Math.ceil(cleanPhrase.length / 2)))) {
      result = true;
    }
  }  
  if (result) {
    console.log(phrase + ' is a palindrome');
  } else {
    console.log(phrase + ' is not a palindrome');    
  }
};
​
//testing helper function
//console.log(removeSpaces(' abc jk'));
//console.log(removeSpaces('ab cjk '));
​
//main tests
isPalindrome(test1);
isPalindrome(test2);
isPalindrome(test3);
isPalindrome(test4);
​
//edge cases
isPalindrome(test5);
isPalindrome(test6);
​
//testing input with spaces
isPalindrome(test7);
​
//testing input with upper case and lower case chars
isPalindrome(test8);
isPalindrome(test9);
​
/* resources used
https://www.palindromelist.net/
*/</script></body>
</html>
    