Maps and Sets
Set Membership
Check whether a value belongs to a set.
Set Membership
set_has.js
const role = "viewer";
const canEdit = new Set(["admin", "editor"]).has(role);
const label = canEdit ? "allowed" : "blocked";
console.log("role=" + role);
console.log("label=" + label);
set-membership
Use `.has(value)` when membership matters more than position. A set membership check is clearer than searching through a list by hand.