How to filter complex array whose one property value is the same and the other property value is mas?

Question

As title, purpose is to get array with no duplicated name and value is max.

var data=[{name:'A',value:3},{name:'B',value:5},{name:'A',value:7},{name:'B',value:1},{name:'B',value:12},{name:'A',value:4}];

expected output:

var newData=[];
newData=[{name:'A',value:7},{name:'B',value:12}];

Thanks in advance

Answer 1

1. solution using forEach, Math.max

var data = [
  { name: "A", value: 3 },
  { name: "B", value: 5 },
  { name: "A", value: 7 },
  { name: "B", value: 1 },
  { name: "B", value: 12 },
  { name: "A", value: 4 },
];

const dict = {};
data.forEach(({ name, value }) => {
  dict[name] = Math.max(value, dict[name] ?? Number.MIN_VALUE);
});

const result = Object.entries(dict).map((o) => {
  const [name, value] = o;
  return { name, value };
});

console.log(result);

2. Using simple forEach and if condition.

var data = [{
    name: "A",
    value: 3
  },
  {
    name: "B",
    value: 5
  },
  {
    name: "A",
    value: 7
  },
  {
    name: "B",
    value: 1
  },
  {
    name: "B",
    value: 12
  },
  {
    name: "A",
    value: 4
  },
];

const dict = {};
data.forEach(({ name, value }) => {
  if (dict[name]) {
    if (dict[name] < value) dict[name] = value;
  } else {
    dict[name] = value;
  }
});

const result = Object.entries(dict).map((o) => {
  const [name, value] = o;
  return { name, value };
});

console.log(result);