For beginner's
IntuitionApproachComplexity
Time complexity:

Space complexity:
Code
# Intuition
<!-- Describe your first thoughts on how to solve this problem. -->

# Approach
<!-- Describe your approach to solving the problem. -->

# Complexity
- Time complexity:
<!-- Add your time complexity here, e.g. $$O(n)$$ -->

- Space complexity:
<!-- Add your space complexity here, e.g. $$O(n)$$ -->

# Code
```javascript []
var reduce = function(nums, fn, init) {
    let result = init;
    for(let i=0;i<nums.length;i++){
        result = fn(result,nums[i]);
    }
    return result; 
};
```
['JavaScript']