Nodejs Utililty Methods Array Same Structure

Array.prototype.sameStructureAs = function(a2) {
  let isSame = true;
  (function recurse(arr1, arr2){
    if (!arr1 || !arr2) {
      isSame = false;
      return;
    if (arr1.length !== arr2.length) {
      isSame = false;
...

Array.prototype.sameStructureAs = function (other) {
  const stringify = a => `[${a.map(b => Array.isArray(b) ? stringify(b) : '|').join('')}]`
  return Array.isArray(other) ? stringify(this) === stringify(other) : false

Array.prototype.sameStructureAs = function (other) {
  if ( this.length !== other.length ) return false;
  for ( var i = 0; i < this.length; i++ ){
    if (Array.isArray(this[i]) && Array.isArray(other[i])) {
      if (!this[i].sameStructureAs(other[i])) return false;
    } else if (Array.isArray(this[i]) || Array.isArray(other[i])){
      return false;
  return true;
};

Array.prototype.sameStructureAs = function (other) {
  var helper = function(a,b){
    if(!isArray(b))
      return false;
    for(i in a){
      if(b[i]===undefined || isArray(a[i])!==isArray(b[i]) || isArray(a[i]) && !a[i].sameStructureAs(b[i]))
        return false;
    return true;
...

Array.prototype.sameStructureAs = function (other) {   
  if (!Array.isArray(other)) return false;
  function transform(array) {
    return array.map(item => Array.isArray(item) ? [transform(item)] : "0");
  return JSON.stringify(transform(this)) === JSON.stringify(transform(other));
};
console.log([ 1, [ 1, 1 ] ].sameStructureAs( [ 2, [ 2, 2 ] ] ));
console.log([ [ [ ], [ ] ] ].sameStructureAs( [ [ [ ], [ ] ] ] ))
...

Array.prototype.sameStructureAs = function(other) {
  if (Array.isArray(other) === false) {
    return false;
  return compareArrays(this, other);
};
function compareArrays(arr1, arr2) {
  if (arr1.length !== arr2.length) {
    return false;
...

Array.prototype.sameStructureAs = function (other) {
  return this && other && Array.isArray(this) === Array.isArray(other) && this.every(function(element, i) {
    if (Array.isArray(element)) {
      return element.sameStructureAs(other[i]);
    return element && other[i] && Array.isArray(element) === Array.isArray(other[i]);
  });
};

Array.prototype.sameStructureAs = function (other) {
  if(other.constructor !== Array){
    return false;
  } else {
    emptyNested(this);
    emptyNested(other);
    var arr1Str = JSON.stringify(this);
    var res1 = '';
    var arr2Str = JSON.stringify(other);
...