let nums = [2,7,11,15],target = 0;
var twoSum = function(nums,target){
let map = new Map();
for(let i = 0;i<nums.length;i++){
let diff = target-nums[i]
console.log('diff',diff)
if(map.has(diff)){
return [map.get(diff),i]
}
map.set(nums[i],i)
}
console.log('map',map)
}
twoSum(nums,target)