JSFiddle - React, Tailwind, and code Playground

JavaScript

var userId, usersObj, usersMap;

usersObj = {
    1: "sally",
    2: "bob",
    3: "jane"
};


console.log(usersObj[1]); //logs "sally", toString called on 1

for (userId in usersObj) {
   console.log(userId, typeof userId); //logs 1..3, "string"
   if (userId === 1) {
     console.log("This is never logged because userId is a string.");
   }
}

usersMap = new Map();
usersMap.set(1, "sally");
usersMap.set(2, "bob");
usersMap.set(3, "jane");

console.log(usersMap.get(1)); //logs "sally"
usersMap.forEach(function (userId, name) {
  console.log(userId, typeof userId); //logs 1..3, "number"
  if (userId === 1) {
     console.log("We found sally.");
  }
});