# Write a javascript code to flatten the given array without using flattened function.

function flattenArray(arr){ let flattened = \[\]; function flatten(ArrElem){ for(let i=0;i<ArrElem.length; i++){ if(Array.isArray(ArrElem\[i\])){ flatten(ArrElem\[i\]) } else{ flattened.push(ArrElem\[i\]) } } } flatten(arr) return flattened }

let arr = \[1, 2, \[3\], 4, \[5, 6, \[7, 8\], \[9,\[10,\[11,\[12,\[13\]\]\]\]\]\]\]; console.log(flattenArray(arr))