adding-new-napi-api.md

2020-01-31

Contributing a new API to N-API

N-API is Node.js's next generation ABI-stable API for native modules. While improving the API surface is encouraged and welcomed, the following are a set of principles and guidelines to keep in mind while adding a new N-API API.

  • A new API must adhere to N-API API shape and spirit.
    • Must be a C API.
    • Must not throw exceptions.
    • Must return napi_status.
    • Should consume napi_env.
    • Must operate only on primitive data types, pointers to primitive datatypes or opaque handles.
    • Must be a necessary API and not a nice to have. Convenience APIs belong in node-addon-api.
    • Must not change the signature of an existing N-API API or break ABI compatibility with other versions of Node.js.
  • New API should be agnostic towards the underlying JavaScript VM.
  • New API PRs must have a corresponding documentation update.
  • New API PRs must be tagged as n-api.
  • There must be at least one test case showing how to use the API.
  • There should be at least one test case per interesting use of the API.
  • There should be a sample provided that operates in a realistic way (operating how a real addon would be written).
  • A new API should be discussed at the N-API team meeting.
  • A new API addition must be signed off by at least two members of the N-API team.
  • A new API addition should be simultaneously implemented in at least one other VM implementation of Node.js.
  • A new API must be considered experimental for at least one minor version release of Node.js before it can be considered for promotion out of experimental.
    • Experimental APIs must be documented as such.
    • Experimental APIs must require an explicit compile-time flag (#define) to be set to opt-in.
    • Experimental APIs must be considered for backport.
    • Experimental status exit criteria must involve at least the following:
      • A new PR must be opened in nodejs/node to remove experimental status. This PR must be tagged as n-api and semver-minor.
      • Exiting an API from experimental must be signed off by the team.
      • If a backport is merited, an API must have a down-level implementation.
      • The API should be used by a published real-world module. Use of the API by a real-world published module will contribute favorably to the decision to take an API out of experimental status.
      • The API must be implemented in a Node.js implementation with an alternate VM.