What is the recommended way to filter Objects with Unique property in the array in JS?

Question

How to filter objects in array based on unique property here i have an array where KEY is the key value in the objects. How to filter the objects where key value is unique. Key

Answer 1

I would go with reduce(), collecting unique elements into a Map (it even preserves insertion order, if that is expected), and packing it back to an array at the end:

var array = [{
  "KEY": "00001",
  "ID": "1234",
  "ID_DESC": "1234",
  "NOT_UNIQUE_VALUE": "119.0",
  "NOT_UNIQUE_TYPE": "this is not unique"
}, {
  "KEY": "00001",
  "ID": "1234",
  "ID_DESC": "1234",
  "NOT_UNIQUE_VALUE": "11019.0",
  "NOT_UNIQUE_TYPE": "not unique type"
}, {
  "KEY": "00002",
  "ID": "2468",
  "ID_DESC": "2468",
  "NOT_UNIQUE_VALUE": "195.0",
  "NOT_UNIQUE_TYPE": "not unique type",
}, {
  "KEY": "00002",
  "ID": "2468",
  "ID_DESC": "2468",
  "NOT_UNIQUE_VALUE": "195.0",
  "NOT_UNIQUE_TYPE": "not unique type",
}]

var result = Array.from(array.reduce((m,o) => {
  if(!m.has(o.KEY))
    m.set(o.KEY, o);
  return m;
}, new Map()).values());

console.log(result)