var obj = { undefined: 1, NaN: 2, Infinity: 3, "-Infinity": 4, null: 5 };
console.log(
    obj[void 0],
    obj[undefined],
    obj["undefined"],
    obj[0 / 0],
    obj[NaN],
    obj["NaN"],
    obj[1 / 0],
    obj[Infinity],
    obj["Infinity"],
    obj[-1 / 0],
    obj[-Infinity],
    obj["-Infinity"],
    obj[null],
    obj["null"]
);