2625. Flatten Deeply Nested Array.js

var flat = function (arr, n) {
    // if n = 0 then we return arr or if all the element of array is 
    // integer (not an array) we return arr.
    if(n == 0 || arr.every((item) => !Array.isArray(item))) return arr;
    const result = [];
    for(let i=0;i<arr.length;i++)
      if(Array.isArray(arr[i]))
        result.push(...arr[i]);
      else
        result.push(arr[i]);
    return flat(result,n-1);
};