Please look at your browser's console.
<script>
function print(str) {
  console.log(str);
}

class ObjectWithMembers {
  constructor(){
    this.x = 1000000;
    this.y = 1000000;
  }
}

function ObjectWithMembersFunc() {
  this.x = 1000000;
  this.y = 1000000;
}

class ObjectNoMembers {
  constructor(){
  }
}

function ObjectNoMembersFunc() {
}

var count = 1e8;
var stash;

var start = performance.now();
for (var i = 0; i < count; ++i) {
  stash = new ObjectWithMembers();
}
print("Object with members class: " + (performance.now() - start));

start = performance.now();
for (i = 0; i < count; ++i) {
  stash = new ObjectWithMembersFunc();
}
print("Object with members function: " + (performance.now() - start));

start = performance.now();
for (i = 0; i < count; ++i) {
  stash = new ObjectNoMembers();
}
print("Object without members class: " + (performance.now() - start));

start = performance.now();
for (i = 0; i < count; ++i) {
  stash = new ObjectNoMembersFunc();
}
print("Object without members function: " + (performance.now() - start));

start = performance.now();
for (i = 0; i < count; ++i) {
  stash = {};
}
print("object literal: " + (performance.now() - start));
</script>