nodejs

One thread runs every callback in a Node process, so anything that holds it holds the whole program. Three biases decide most calls:

• The engines.node floor decides what may be written, not the node binary on the machine.
• Read an API's stability index before depending on it. Node ships an API for years before committing to it, and an experimental one can be deleted without a deprecation cycle.
• Check the standard library before adding a dependency. It absorbed fetch, a test runner, a file watcher, glob, SQLite, .env parsing, a script runner, and TypeScript execution.

Node Version

engines.node in package.json is the floor a project claims. Read it before writing code and never reach for an API above it. Nothing enforces it at run time — Node never reads the field, and npm checks it only under engine-strict=true — so the floor holds by discipline and by CI running the oldest major it names.

The installed binary is not the floor. node --version reports what one machine has, not what the project supports.

Support windows, which decide whether a floor is defensible: