What is the JavaScript equivalent to java LinkedHashSet?

Question

I have a list of lists containing IDs in javascript, I want them to be added to a set which maintains insertion order and has only unique values

Answer 1

This is exactly what JavaScript's Set does. It contains only unique values, and iterates in insertion order. Example:

const s = new Set();
s.add("q");
s.add("x");
s.add("c");
s.add("q"); // duplicate
for (const v of s) {
  console.log(v); // q, x, c -- insertion order
}