<=' operator does not distinguish 0 and null, should be '<=='

[gasp]

let's consider this rule, looking for values between or equals 0 and 1

const rule = { '<=': [0, { var: 'data' }, 1] };

with data being 0, it works

const zeroInput = { data: 0 };
const zeroArrayInput = { data: [0] };
jsonLogic.apply(rule, zeroInput); // returns true
jsonLogic.apply(rule, zeroArrayInput); // returns true

with data being null, this is wrongly interpreted

const nullInput = { data: null };
jsonLogic.apply(rule, nullInput); // returns true, whereas it should be returning false

[jwadhams]

0 <= null is true in JavaScript.

The implementation is literally just calling the language builtin in this case... there's a little extra sugar to allow a three-way-comparison (for "between" like 0 <= X <= 2) but it all boils down to JavaScript, in it's ineffable way, deciding that 0 <= null is true

The implementation already puts all the boring operations (the ones that don't control flow and can be executed depth-first) in the operations object so you could replace the default <= using one of your own design (maybe throwing a type error if you try to compare with NULL) just by using addOperation without having to fork the project itself.

You could also use addOperation to implement an <== operator for your own, then you'd have both tools available. It didn't occur to me in the JsonLogic spec because no language I work in day-to-day has one.