basilisk55/js/xpconnect/tests/unit/test_structuredClone.js

function run_test() {
  var sb = new Cu.Sandbox('http://www.example.com',
                          { wantGlobalProperties: ["structuredClone"] });

  sb.equal = equal;

  sb.testing =  Components.utils.cloneInto({xyz: 123}, sb);
  Cu.evalInSandbox(`
    equal(structuredClone("abc"), "abc");

    var obj = {a: 1};
    obj.self = obj;
    var clone = structuredClone(obj);
    equal(clone.a, 1);
    equal(clone.self, clone);

    var ab = new ArrayBuffer(1);
    clone = structuredClone(ab, {transfer: [ab]});
    equal(clone.byteLength, 1);
    equal(ab.byteLength, 0);

    clone = structuredClone(testing);
    equal(clone.xyz, 123);
  `, sb);
}