How to implement and ship a proposal

[littledan]

TC39 proposals are implemented at all different stages, in native implementations, transpilers, polyfills, tools and more. Early implementations play a significant role in TC39 processes, and it would be great to have a document targeting their role, including:

• TC39 appreciates you! In addition to getting features to JS developers, the process of implementation gives detailed sense of the feature within the language as a whole and its various interactions, leading to important insights about the design.
• It's never too early to draft an implementation, but different stages indicate different levels of stability and concreteness. Explain the stage process from that perspective for implementers, in a way which can help guide shipping/flag/semver decisions, including case studies of various projects' policies.
• All kinds of feedback are appreciated from implementers, whether it's about the motivation, high-level design, integration with various other systems, implementation complexity, or the semantics of edge cases. The best way to give feedback is through filing bugs in the GitHub repository. Feel free to make PRs against the draft spec for suggested semantic changes, if you want.
• Champions want to hear from you. If you're working on an implementation and, e.g., are having trouble understanding the proposal or want help with an edge case, get in touch with the champion, either by filing the question as an issue in GitHub, writing them an email, or even asking for a call to go over things.
• It's highly appreciated if you upstream any tests you develop as test262 tests

cc some early implementers; would any of you be interested in helping with this sort of documentation? @caitp @gsathya @arai-a @hzoo @rbuckton @caiolima @jakobkummerow @kmiller68

[hzoo]

Started doing this sort of thing in babel/proposals#26 but I can certainly help document the Babel stuff and give examples of how this has been done in the past and would we'd like to see happen.