Node.js quiz! Can you guess the value?

dse-circ-6.1.0.js

'use strict';

var a = [], b = [a], eq = require('assert').deepStrictEqual;

function dse(x, y) {
  var e;
  try {
    eq(x, y);
    e = '===equal===';
  } catch (err) {
    e = String(err.message || err);
  }
  console.log(e);
  return e;
}

eq(dse(1, 1),   '===equal===');
eq(dse(1, 5),   '1 deepStrictEqual 5');
eq(dse(a, b),   '[] deepStrictEqual [ [] ]');
eq(dse(b, a),   '[ [] ] deepStrictEqual []');
a.push(b);
eq(dse(a, b),   '???');