palindrome

Returns true if the given string is a palindrome, false otherwise.

Convert the string to String.prototype.toLowerCase() and use String.prototype.replace() to remove non-alphanumeric characters from it. Then, use the spread operator (...) to split the string into individual characters, Array.prototype.reverse(), String.prototype.join('') and compare it to the original, unreversed string, after converting it to String.prototype.toLowerCase().

const palindrome = (str) => {
  const s = str.toLowerCase().replace(/[\W_]/g, "");
  return s === [...s].reverse().join("");
};

palindrome("taco cat"); // true