n个数组的对称差

sym.js

// 先求两个的对称差，用求得的结果与其后的数组重复之前步骤
function sym() {
    var ans = [];
    var args = Array.prototype.slice.call(arguments);
    var len = args.length;
    var two;
    function uniq(arr) {
    	var output = [];
    	var objMark = {};
    	arr.forEach(function(item, index) {
    		if (objMark[item] == null) {
    			output.push(item);
    			objMark[item] = 1;
    		}
    	})
    	return output;
    }
    if (len < 2) return false;
    if (len > 2) {
    	two = args.splice(0, 2);
    } else {
    	two = args;
    }
    if (len === 2) {

    	for (var i = 0; i < 2; i++) {
    	    var tempArr = two[i].filter(function(el) {
    	    	var j;
    	    	var allHas = true;

    	        for (j = 0; j < 2; j++) {
    	            if (Array.isArray(two[j]) && two[j] !== two[i]) {
    	                if (two[j].indexOf(el) !== -1) {
    	                    return false;
    	                }
    	            }
    	        }
    	        return true;
    	    });
    	    ans = ans.concat(tempArr);
    	}
    	return uniq(ans);
    }

    return sym.apply(this, [sym(two[0], two[1])].concat(args) );

}

var a = sym([3, 3, 3, 2, 5], [2, 1, 5, 7], [3, 4, 6, 6], [1, 2, 3], [5, 3, 9, 8], [1]);
console.log(a);