You have to check if the string you get as an input is a palindrome and return true if it is, and false otherwise.
You may use regular expressions (RegExp) to remove unwanted characters from the string.
You may use Array.prototype.split and Array.prototype.join methods or for loop.
You may lowercase the string using String.prototype.toLowerCase.
Solution ahead!
function palindrome(str) {
var normalizedStr = str.replace(/[\W_]/g, '').toLowerCase();
var reverseStr = normalizedStr.split('').reverse().join('');
return normalizedStr === reverseStr;
}function palindrome(str) {
str = str.toLowerCase().replace(/[\W_]/g, '');
for(var i = 0, len = str.length - 1; i < len/2; i++) {
if(str[i] !== str[len-i]) {
return false;
}
}
return true;
}We use regular expressions to replace any uppercase letter into a lowercase. Then we check if the string is the same as the reversed string using split() to split the original string by characters, then reverse and then join it back together.
function palindrome(str) {
// make all letters lowercase and remove non-alphanumeric characters
str = str.toLowerCase();
str = str.replace(/[^a-z|1-9]/g, "");
// if the length of the string is 0 then it is a palindrome
if (str.length === 0){
return true;
}
// if the first letter and the last letter of the string do not equal eachother then it is not a palindrome
if (str[0] !== str[str.length-1]){
return false;
}
//Else, run the function without the first and last characters.
else{
return palindrome(str.slice(1,str.length - 1));
}
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