Filter Elements from Array
Given an integer array arr and a filtering function fn, return a new array with a fewer or equal number of elements.
The returned array should only contain elements where fn(arr[i], i) evaluated to a truthy value.
Please solve it without the built-in Array.filter method.
Example 1:
Input: arr = [0,10,20,30], fn = function greaterThan10(n) { return n > 10; }
Output: [20,30]
Explanation:
const newArray = filter(arr, fn); // [20, 30]
The function filters out values that are not greater than 10
Example 2:
Input: arr = [1,2,3], fn = function firstIndex(n, i) { return i === 0; }
Output: [1]
Explanation:
fn can also accept the index of each element
In this case, the function removes elements not at index 0
Example 3:
Input: arr = [-2,-1,0,1,2], fn = function plusOne(n) { return n + 1 }
Output: [-2,0,1,2]
Explanation:
Falsey values such as 0 should be filtered out
/**
* @param {number[]} arr
* @param {Function} fn
* @return {number[]}
*/
var filter = function(arr, fn) {
let result = [];
for(let i=0; i<arr.length; i++){
if(fn(arr[i],i)){
result.push(arr[i])
}
}
return result;
};