LeetCode Two Sum Problem

Two Sum.js

/**
 * @param {number[]} nums
 * @param {number} target
 * @return {number[]}
 */
var twoSum = function(nums, target) {
    previousValues = {}; // Set Previous Hash Values
for (let i = 0; i < nums.length; i++){ // Loop through entire array
    currentNum = nums[i]; // Get Current Loop Number
    neededNum = target - currentNum; //Calculate Number Needed
    index2 = previousValues[neededNum];// Check to see if number needed is in current hash table
    if(index2 != null){ // If it is return index 2  and iteration number
        return [index2,i];
    }else{ // if it is Null save it in hash table
        previousValues[currentNum] = i;
    }
}
};