serialize(-0) returns "0" - negative zero is lost on round-trip #234

Version: 7.1.2 (latest on npm)

serialize-javascript goes out of its way to preserve the numeric values JSON can't represent - NaN, Infinity, and -Infinity are all emitted as placeholders so they round-trip correctly. -0 falls through the same JSON.stringify path and comes back as plain 0, so a serialized-then-evaluated value is no longer Object.is-equal to the original.

Repro:

const serialize = require('serialize-javascript');

const s = serialize(-0);
console.log(s);                          // "0"
console.log(Object.is(eval('(' + s + ')'), -0)); // false

console.log(serialize({ startTime: -0 })); // {"startTime":0}

For comparison, the sibling edge cases do round-trip:

Object.is(eval(serialize(NaN)), NaN) // ...evaluates NaN via placeholder
eval(serialize(Infinity))            // Infinity
eval(serialize(-Infinity))           // -Infinity

Why it matters: -0 is a real, observable value in JS (Object.is(-0, 0) === false, 1 / -0 === -Infinity). Code that round-trips state through serialize-javascript (worker messaging, SSR state injection, template embedding - the library's main use cases) silently loses the sign. A consumer computing 1 / value after deserialization gets Infinity instead of -Infinity.

Possible fix: in the number branch, detect Object.is(obj, -0) (or obj === 0 && 1 / obj === -Infinity) and emit a placeholder alongside the existing NaN/Infinity/-Infinity ones.

Happy to take a look at a PR if that would help.