JSFiddle - React, Tailwind, and code Playground

JavaScript

let obj = {}, map = new Map();

let users = ["John", "Murray", "Jane", "Jane", "Anne", "John", "Murray", "Jane", "Jane", "Anne"];

for (let i = 0; i < users.length; i++) {
  obj[i] = i;
  map.set(i, i);
}

let result;

console.time('Object'); 
result = obj.hasOwnProperty("Anne"); 
console.timeEnd('Object');

console.time('Map'); 
result = map.has("Anne"); 
console.timeEnd('Map');