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It doesn’t seem conveniently possible. What can you do? Something horrible, as always.

let tuple = (function() {
 let map = new Map();
 function tuple() {
 let current = map;
 let args = Object.freeze(Array.prototype.slice.call(arguments));
 for (let item of args) {
 if (current.has(item)) {
 current = current.get(item);
 } else {
 let next = new Map();
 current.set(item, next);
 current = next;
 }
 }
 if (!current.final) {
 current.final = args;
 }
 return current.final;
 }
 return tuple;
})();

And voilà.

let m = new Map();
m.set(tuple(3, 5), [tuple(3, 5, 3), tuple(3, 5, 4)]);
m.get(tuple(3, 5)); // [[3, 5, 3], [3, 5, 4]]