super nitpick—if an observable cell evaluates to -0, it is printed as 0, whereas in Node and browser consoles, it is printed as -0.
(-0).toString() is "0", so you have to do something like this instead (reference)
const isNegativeZero = (x) => x === 0 && (1/x < 0);
const print = (x) => isNegativeZero(x) ? "-0" : x;
print(-0); // => "-0"