var array = [1];
var arrayLike = {0:1, length:1};
var fakeArrayLike = {length:1, height:2};
var window = window;
var fn = function() {};

alert(isArrayLike(array)); // true
alert(isArrayLike(arrayLike)); // true
alert(isArrayLike(fakeArrayLike)); // true | must be false
alert(isArrayLike(window)); // true | must be false
alert(isArrayLike(fn)); // false | must be false
// -------------------

/**
 * @param {*} any
 * @returns {Boolean}
 */
function isArrayLike(any) {
    return isObject(any) && any.hasOwnProperty('length');
}

/**
 * @param {*} any
 * @returns {Boolean}
 */
function isObject(any) {
    return any !== null && typeof any === 'object';
}

var collection = document.getElementsByTagName('body');
alert(collection.splice);
alert(collection.length);

/**
 * @private
 * @param {*} obj
 * @return {boolean} Returns true if `obj` is an array or array-like object (NodeList, Arguments,
 *                   String ...)
 */
function isArrayLike(obj) {
  if (obj == null || isWindow(obj)) {
    return false;
  }

  var length = obj.length;

  if (obj.nodeType === 1 && length) {
    return true;
  }

  return isString(obj) || isArray(obj) || length === 0 ||
         typeof length === 'number' && length > 0 && (length - 1) in obj;
}

function isArraylike( obj ) {
	var length = obj.length,
		type = jQuery.type( obj );

	if ( type === "function" || jQuery.isWindow( obj ) ) {
		return false;
	}

	if ( obj.nodeType === 1 && length ) {
		return true;
	}

	return type === "array" || length === 0 ||
		typeof length === "number" && length > 0 && ( length - 1 ) in obj;
}

function likeArray(item) {

  if( !('length' in item) ) return false;

  for(var index = 0; index < item.length; index++){
    if( !(index in item) ) return false;
  }

  return true;
}

Symbol.iterator in object

var object = {'12.24': 1, foo: NaN, length: 1};
      
alert(likeArray(object));
      
function likeArray(item) {

  if( !('length' in item) ) return false;

  var keys = Object.keys(item);
  var indexCnt = 0;

  for(var i = 0; i < keys.length; i++){
    var key = keys[i]
    if(+key != key) continue;
    indexCnt++
  }

  return indexCnt === item.length;
}

alert(Symbol.iterator in document.getElementsByTagName('body'));
alert(Symbol.iterator in document.querySelectorAll('body'));

NodeList.prototype[Symbol.iterator] = function*() {
    for (let i = 0; i < this.length; i++) {
        yield this[i];
    }
}

function likeArray(item) {
  if( item == null ) return false;
  if( item === window ) return false;
  if( !('length' in item) ) return false;
  if( typeof item === 'function' ) return false;
  if( item.length === 0 ) return true;
  return ( item.length - 1 ) in item
}

var array = [1];
var arrayLike = {0:1, length:1};
var fakeArrayLike = {length:1, height:2};
var window = window;
var fn = function() {};
var fake1 = {foo: NaN, length: 1};
var fake2 = {'12.24': 1, length: 1};
var fake3 = '';
var fake4 = '1';

console.log(isArrayLike(document.getElementsByTagName('body')) === true, 1);
console.log(isArrayLike(document.querySelectorAll('body')) === true, 2);
console.log(isArrayLike(array) === true, 3);
console.log(isArrayLike(arrayLike) === true, 4);
console.log(isArrayLike(fakeArrayLike) === false, 5);
console.log(isArrayLike(window) === false, 6);
console.log(isArrayLike(fn) === false, 7);
console.log(isArrayLike(fake1) === false, 8);
console.log(isArrayLike(fake2) === false, 9);
console.log(isArrayLike(fake3) === false, 10);
console.log(isArrayLike(fake4) === false, 11);


function isArrayLike(item) {
  if( typeof item === 'string' ) return false;
  if( item == null ) return false;
  if( item === window ) return false;
  if( !('length' in item) ) return false;
  if( typeof item === 'function' ) return false;
  if( item.length === 0 ) return true;
  return ( item.length - 1 ) in item
}

function toArray(item){
  if( likeArray(item) ) return [].slice.call(item);
  return [item]
}

<a href="https://pp.vk.me/c411223/v411223005/2575/Cr9yOId2NPc.jpg" download="wow-pic.jpg">Картинка сохранится под оригинальным именем</a>