1const originalData = [
2  { "investor": "Sue",   "value":  5,   "investment": "stocks"  },
3  { "investor": "Rob",   "value": 15,   "investment": "options" },
4  { "investor": "Sue",   "value": 25,   "investment": "savings" },
5  { "investor": "Rob",   "value": 15,   "investment": "savings" },
6  { "investor": "Sue",   "value":  2,   "investment": "stocks"  },
7  { "investor": "Liz",   "value": 85,   "investment": "options" },
8  { "investor": "Liz",   "value": 16,   "investment": "options" },
9];
10
11const newData = [
12  { "investor": "Sue",   "stocks": 0,   "options": 0,   "savings": 0 },
13  { "investor": "Rob",   "stocks": 0,   "options": 0,   "savings": 0 },
14  { "investor": "Liz",   "stocks": 0,   "options": 0,   "savings": 0 },
15];
16
17for (let {investor, value, investment} of originalData) {
18  newData.find(x => x.investor === investor)[investment] += value;
19}
20
21console.log(newData);

1The first element that will be found by that function
2const f = array1.find(e => e > 10);