js is mutant C with dementia - hacked together over over a fortnight, full of inconsistencies and weird corners.

    console.log(1 + "2"); // "12"
    console.log(1 - "2"); // -1
    console.log(NaN === NaN); // false
    console.log(+0 === -0); // true

    const obj = {};
    console.log(obj.foo); // undefined, not an error