/**
 * @param {string[]} words
 * @return {number[][]}
 */
var palindromePairs = function(words) {
  const index = [];
  for(let i = 0; i < words.length; i++) {
    for (let j = 0; j < words.length; j++) {
      if (i !== j) {
        if (isPalindrome(words[i] + words[j])) { index.push([i, j]); }
      }
    }
  }
  return index;
};

const isPalindrome = (word) => {
  const len = word.length / 2 + 1;
  const wordLength = word.length - 1;
  for (let i = 0; i < len; i++){
    if (word[i] !== word[wordLength - i]) {
      return false;
    }
  }
  return true;
};