In my limited testing thus far doing something like ^([\[{\(])?([\]}\)])?$ will operate more slowly than ^([\[{\(]?)([\]}\)]?)$ even on small strings. In my current limited testing I see a ~3% difference

Comparison of methods such as:

if (a in b) {
  a[b]();
}

if (a && a[b]) {
  a[b]();
}

a && a[b] && a[b]();

and other methods for checking for the presence of the object.

Want to compare the cost for the functionality of prototypal inheritance within ES6 and libraries. This should include both a "deep" inhertiance (see the user land modules for what this means) and the shallow version that Object.assign(...) implements.

Object.assign(target, parent);

jQuery.extend(target, parent);

Other versions as well including extend on NPM, LoDash, etc. and the deep versions also.

Looking at different methods of manipulating Sets would be ideal. Doing things like the following:

Merging two sets

function mergeSets(setA, setB) {
  setA.merge(setB);
  return setA;
}

function mergeSetsAlt(setA, setB) {
  return setA.concat(setB);
}

Returning a new instance of a Set

function cloneSet(setA) {
  var setB = new Set();
  setB.merge(setA);
  return setB;
}

function cloneSetAlt(setA) {
  return setA.slice();
}

Similar to what I did here but a more generic version that compares a number of methods.