Frequently Asked Questions

Differences from Node.js

Even though Membrane programs are written in TypeScript/JavaScript, they work differently from typical Node.js or browser programs in a couple of fundamental ways:

1. Membrane programs are durable
   • There’s no need to store data in external databases or files—use the state object instead
   • Actions can run indefinitely (e.g. await’ing an email reply)
2. Membrane programs are event-sourced
   • Each program has a write-ahead log that records all effects, which are then processed by membrane separately
   • That means all actions taken by a program are guaranteed to be in the logs—if it’s not in the logs, it didn’t happen
3. All communication happens through the graph
   • Even fetch is implemented using graph nodes

Do npm modules work?

Many npm modules can be used in Membrane, but not all of them, especially if they depend on specific Node.js APIs that we don’t yet support. Please reach out if you find a package that fails to load due to missing functionality, we would be more than happy to implement it.

To use an npm package, create a package.json file, add any packages to dependencies, and save the program. We’d like to close any runtime support gaps, so feel free to reach out at contact@membrane.io if you run into compatibility issues.