When will CommonJS modules (require) be deprecated and removed?

[trusktr]

Just curious if this is planned to happen, or is it something no one is thinking about yet?

[mmarchini]

@nodejs/modules has probably discussed this extensively, and so have many other project members.

Sharing my opinion on this: deprecation and removal of CommonJS would be extremely disruptive to the entire ecosystem, and would cause more pain to our users than Python users experienced with migrating to Python 3. As such, deprecation is unlikely to happen in the mid-term future, if at all.

[ljharb]

I don’t see any point in ever doing that - CJS isn’t legacy, it’s just one of two first-class module systems in node.

[jkrems]

I think it’s too early to come up with a clear timeline for this. We’re just approaching the first non-trivial module based apps being possible (without compiling from something else, at least rewriting imports). And there’s a huge amount of code in the ecosystem and even more so in various companies that’s based on CJS - much of which may be non-trivial to convert to ESM (since ESM lacks certain features and is fully async).

So - I wouldn’t go as far as Jordan and say “never” but I’d say “long enough that it could as well be never at this point”.

[jasnell]

Still way too early to even consider, especially given that ESM is still experimental

[devsnek]

Seems answered, closing

[jsumners]

I hate to revive a long closed issue, but I don't think this topic is resolved. At least one major module developer is planning to remove support for CJS from their modules by the end of 2021 -- https://twitter.com/sindresorhus/status/1349294527350149121

I think without a clear signal from core that CJS is deprecated, module authors are going to have a maintenance nightmare on their hands. As a result of the above announcement, @mcollina has asked the Fastify community if we should do the same fastify/fastify#2847.

What we will have is a hodgepodge of incompatible modules and fragmentation throughout the community. CJS codebases that wish to remain CJS will have to try and find replacement modules, fork and maintain older versions of the modules they use, or refactor their code base to either load modules asynchronously or convert to ESM.

Personally, as a backend only developer, I have not seen any "oh I gotta have that" benefits to ESM that would convince me to shift everything over. But if core were to come out and say "look, keeping both around is going to be a problem so we are deprecating CJS," then I'd basically have no choice. And it would give clarity to the community at-large as to what their maintenance path forward should be.

cc: @sindresorhus for your own visibility to whatever discussion happens here.

[ljharb]

It isn’t deprecated, so no such signal should exist. CJS and ESM are both first-class module systems in node.

If a package switches to only ESM, that package has chosen to exclude CJS users, and those users will either switch to ESM, or more likely find alternatives that don’t capriciously exclude them (since providing an ESM wrapper on a CJS package is relatively trivial).

[WebReflection]

My 2c,
today I wrote this file because CommonJS can still do things ESM cannot, and work in both cases (as that file does).

There was a lot of effort to make dual packaging reality, and for personal experience I can say it works fine with everything out there (bundlers, CJS only projects, ESM ony projects), plus cache invalidation/hot reloading is still extremely hard in ESM, so that choosing to ditch CJS when there are tools (ascjs/ucjs to name two) that makes dual packaging a no-brainer, beside the only constraint that is live bindings, sounds a bit "capricious" indeed.

[mcollina]

There is no plan to deprecate cjs.

[jsumners]

There is no plan to deprecate cjs.

I am aware. My statement is that some discussion should be had about if a plan to do so should be created. In my view, there is clearly a painful future in store if it isn't deprecated.

To be clear, I have no desire to use ESM. But if having both CJS and ESM supported means there will be a fragmented community, then only one should be supported.