JS: Filter array of objects by max value per category

Question

What is most efficient / elegant way to achieve sql-like filtering effect. I want to filter them and get only that objects which are max value in some group.

This is

Answer 1

I love to use lodash for stuff like this. It's very functional and therefore very clear and straightforward.

Take a look at the following code:

const DATA = [
  {
    name: "bathroom",
    value: 54,
    timeStamp: 1562318089713
  },
  {
    name: "bathroom",
    value: 55,
    timeStamp: 1562318090807
  },
  {
    name: "bedroom",
    value: 48,
    timeStamp: 1562318092084
  },
  {
    name: "bedroom",
    value: 49,
    timeStamp: 1562318092223
  },
  {
    name: "room",
    value: 41,
    timeStamp: 1562318093467
  }
];

let max = _
  .chain(DATA)
  .groupBy('name')
  .sortBy('value')
  .map(o => _(o).reverse().first())
  .flatten()
  .value();

console.log(max); // returns [{"name":"bathroom","value":55,"timeStamp":1562318090807},{"name":"bedroom","value":49,"timeStamp":1562318092223},{"name":"room","value":41,"timeStamp":1562318093467}]