twoSum.js

//input = array, number
//output = array 

//test case
//[2, 7, 11, 15], 13
//[0, 2]

function twoSum (array, number) {
  var solutionObject = {};
  for (let i = 0; i < array.length; i++) {
    const target = number - array[i];
    if (target in solutionObject) {
      return [solutionObject[target], i];
    } else {
      solutionObject[array[i]] = i;
    }
  }
}

twoSum([4, 5, 10], 14);