I am learning JS on freecodecamp and am stuck on a problem. I am creating a palindrome checker. My code almost works. However, there is only one word that is not passing the test and that is almostomla. It is not a palindrome yet my code returns true. I have tried several things. Even rewrote the code and used the while loop but nothing seems to help. There is a solution at the freeCodecamp web but I have written the code in a different way and am unable to figure my mistake out.
Here is my code.
let reversedStr = [];
function palindrome(str) {
let d = str.replace(/[^a-zA-Z0-9]/g, "").toLowerCase();
for (let i = d.length - 1; i >= 0; i--) {
reversedStr.push(d[i]);
}
for (let j = 0; j < str.length; j++) {
if (reversedStr[j] == d[j]) {
return true;
} else {
return false;
}
}
}
console.log(palindrome("almostomla"));This line if (reversedStr[j] == d[j]) {return true; returns as soon as the character matches at both the index. It does not check rest of the characters.
In fact you can just return as soon as the character in both index does not match.
Also note the reversedStr has to be inside the function. Else it will contain previous values
function palindrome(str) {
let reversedStr = [];
let d = str.replace(/[^a-zA-Z0-9]/g, "").toLowerCase();
for (let i = d.length - 1; i >= 0; i--) {
reversedStr.push(d[i]);
}
for (let j = 0; j < str.length; j++) {
if (reversedStr[j] !== d[j]) {
return false;
}
}
return true
}
console.log(palindrome("almostomla"));
console.log(palindrome("1221"));Your code returns "true" or "false" after first match - it checks that 'a' is equal to 'a' and returns true.
You can return "false" from inside of cycle only if you found duplicated letter else return true after the cycle ends.