I think @Gordon summed it up well, but in addition to the constraints the application space differs too. As a microcontroller, the Espruino efficiently handles sensor and actuator device interfaces to collect and process real world data. NodeJS on the other hand builds Internet web services. Personally, I don't favor the notion of using an OS dependent system such as NodeJS to triddle hardware, nor the naive idea of exposing a primitive microcontroller board like Espruino directly to the Internet. Remember Maslow's hammer -- when all you have is a hammer, everything looks likes a nail. Espruino and NodeJS, while both JavaScript based give us two different tools, so choose the best tool for the job.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
I think @Gordon summed it up well, but in addition to the constraints the application space differs too. As a microcontroller, the Espruino efficiently handles sensor and actuator device interfaces to collect and process real world data. NodeJS on the other hand builds Internet web services. Personally, I don't favor the notion of using an OS dependent system such as NodeJS to triddle hardware, nor the naive idea of exposing a primitive microcontroller board like Espruino directly to the Internet. Remember Maslow's hammer -- when all you have is a hammer, everything looks likes a nail. Espruino and NodeJS, while both JavaScript based give us two different tools, so choose the best tool for the job.