JSFiddle - React, Tailwind, and code Playground

JavaScript

var occ = {}
var family = [{
  name: "Mike",
  age: 10
}, {
  name: "Matt",
  age: 13
}, {
  name: "Nancy",
  age: 15
}, {
  name: "Adam",
  age: 22
}, {
  name: "Jenny",
  age: 85
}, {
  name: "Nancy",
  age: 2
}, {
  name: "Carl",
  age: 40
}];

console.log(family.filter(function(x) {
  if (occ[x.name]) return false;
  occ[x.name] = true;
  return true;
}))