JSON.parse Throws — Always Wrap It

The problem:

const data = JSON.parse(userInput);  // Crashes if invalid

User sends malformed JSON. App crashes. Error log floods. Restart loop.

The fix:

function parseJSON<T>(input: string, fallback: T): T {
  try {
    return JSON.parse(input);
  } catch {
    console.error("Invalid JSON:", input);
    return fallback;
  }
}

const data = parseJSON(userInput, {});

Or zod for validation:

const data = z.string().pipe(z.string().transform(JSON.parse)).parse(userInput);

Never trust external data. From the user, from an API, from a file. Always validate. Parse defensively.

Untrusted input is the root cause of 80% of production incidents. JSON.parse is just one vector.

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