JavaScript puzzle: equal, but not the same

+0 and -0 are the only two values that are not the same, but are still considered strictly equal [1]. They can only be distinguished indirectly, by applying a mathematical operation to them that produces distinguishable results. Dividing 1 by zero is one of several operations that does so:

    > 1/-0
    -Infinity
    > 1/+0
    Infinity

    > -Infinity === Infinity
    false

1. “Stricter equality in JavaScript” explores more consequences of strict equality’s special treatment of +0, -0 and NaN.
2. “JavaScript’s two zeros” provides more information on the two zeros. For example, other ways than the above for distinguishing them.