How to write an assert statement in react-native?

I want a quick check like assert(route?.params?.array !== undefined).

The closest I've found is node's assert library. But I don't think that's useable out of the box with React-native. (If it is, I'd accept an answer showing me how!)

I would accept a try catch code where I can catch if array is undefined.

Right now I'm doing something like

try {
    route.params.array.length;
} catch(err) {
    console.log("ERR: looks like array is undefined.");
}

But I would like something less hacky. Also, any suggestions about how to do testing properly in React-Native are welcome.