找到数组间差异算法挑战

找出数组间差异算法挑战
function diff(arr1, arr2) {
var newArr = [];
// Same, same; but different.
arr1.map(function(val1){
    if(arr2.indexOf(val1) === -1){
        newArr.push(val1);
    }else{
        arr2.splice(arr2.indexOf(val1),1);
    }
});
return newArr.concat(arr2);
}

diff([1, 2, 3,6, 5], [1, 2, 3, 4, 5]);

参考http://www.imooc.com/article/18353
参考https://developer.mozilla.org/zh-CN/docs/Web/JavaScript/Reference/Global_Objects/Array
参考https://segmentfault.com/a/1190000010866742
参考http://www.cduyzh.com/JS-intermediate-train/
参考https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every