Have you tried lokijs.js with large amount data for desktop browsers and What is the maximum stoage size of lokijs.js?
On node.js the virtual limit is the amount of RAM utilizable by your process (because Loki works in memory so it can't store more data than it fits in memory). So on a normal dev machine that would be something in the region between 1gb and 3-4gb. In a browser, it's 5MB.