javascript - Counting number of occurrences recursively -

why recursive countoccurence function not working? has subroutine. there way without subroutine? seems in javascript have have closure (subroutine function) counter variable, otherwise gets rewritten every time!

function numoccurencesrecursive(arr, val) {   //base case. check if has length of 1   var count = 0;    function docount(arr, val) {     if (arr[0] === val) {       count++;     } else {       count += docount(arr.slice(1), val)     }     return count;   }    return docount(arr, val); }  console.log(numoccurencesrecursive([2, 7, 4, 4, 1, 4], 4)); // should return 3 returns 1 

i think problem thinking iteratively used recursive approach.

the iterative approach has global variable may updated @ each step:

function numoccurencesiterative(arr, val) {   var count = 0;   for(var i=0; i<arr.length; ++i) if(arr[i] === val) ++count;   return count; } 

however, when using recursive approaches, better avoid global variables.

function numoccurencesrecursive(arr, val) {   if(!arr.length) return 0;   return (arr[0] === val) + numoccurencesrecursive(arr.slice(1), val); }