利用hasOwnProperty给数组去重的面试题分享

var o = { a: 1};
console.log(o.hasOwnProperty('a')); // true
console.log(o.hasOwnProperty('b')); // false

var arr = ['a', 'b', 'c', 'b'];

function uniqueArr(arr){

 var unique = [], temp = {};

 for(var i = 0; i < arr.length; i++){
  if(temp[arr[i]] === undefined){
   temp[arr[i]] = 1;
   unique.push(arr[i]);
  }
 }

 return unique;
}

var o1 = {a:1, b:2},
 o2 = {b:2, a:1},
 o3 = {a:2, b:1};

function isEqual(o1, o2){

 var o1_keys = Object.keys(o1);
 var o2_keys = Object.keys(o1);

 if(o1_keys.length !== o2_keys.length){
  return false;
 }

 o1_keys = o1_keys.sort();
 o2_keys = o2_keys.sort();
 if(o1_keys.join('||') !== o2_keys.join('||')){
  return false;
 }

 var r = true;
 for(var key of o1_keys){
  
  if( !isPrimitive(o1[key] ) && !isPrimitive( o2[key])){
   if(!isEqual(o1[key], o2[key])){
   r = false;
   break;
   }
  } else if(o1[key] !== o2[key]){
   r = false;
   break;
  } 
 }

 return r;


 function isPrimitive(v){
  var type = typeof v;
  return type === 'number' || type === 'string' || type === 'boolean' || v === undefined || v === null; 
 }


}

console.log(isEqual(o1, o2));
console.log(isEqual(o1, o3));
console.log(isEqual({a:1, b:{c:1}}, {b:{c:2}, a:1}));
console.log(isEqual({a:1, b:{c:1}}, {b:{c:1}, a:1}));
console.log(isEqual({a:1, b:{c:1},c:2}, {b:{c:1}, a:1}));
console.log(isEqual({a:1, b:{c:1}}, {b:{c:1}, a:{b:1}}));
console.log(isEqual({a:1, b:function(){}}, {b:function(){}, a:1}));

var f1 = function(){};
var f2 = function(){};

if(f1.toString() === f2.toString()){
 console.log(true);
}