JS中数组去重及求量数组中的相同字符个数

function overMaxStrLen(arr1,arr2){
var comNum = 0;
if(!arr1 || !arr2){
return comNum;
}
var len1 = arr1.length;
var len2 = arr2.length;
var minArr = arr1;
var maxArr = arr2;
if(len1 > len2){
minArr = arr2;
maxArr = arr1;
}
var minStr = minArr.join("");
var maxStr = maxArr.join("");
var minLen = minStr.length;
while(minLen > 0){
if(maxStr.indexOf(minStr[minLen -1]) != -1){
comNum +=1;
}
minLen -=1;
}

return comNum;
}
//将数组arr去重
function remoceRepeat( arr){
arr.sort(); //先排序
var res = [arr[0]];
for(var i = 1; i < arr.length; i++){
if(arr[i] !== res[res.length - 1]){
res.push(arr[i]);
}
}
return res;
}