Method js_add

rhino/src/main/java/org/mozilla/javascript/NativeSet.java:105–110

(
            Context cx, JSFunction f, Object nt, VarScope s, Object thisObj, Object[] args)

    }

    private static Object js_add(
            Context cx, JSFunction f, Object nt, VarScope s, Object thisObj, Object[] args) {
        NativeSet realThis = realThis(thisObj, "add");
        var k = NativeMap.key(args);
        return realThis.js_add(k);
    }

    private Object js_add(Object k) {
        // Special handling of "negative zero" from the spec.