(Question)Is there a way to share code between app and libs?

[NE-SmallTown]

core-js/modules/es.promise.js and core-js-pure/modules/es.promise.js are exactly the same code, the main difference is just that the former has global pollution. If so, why core-js doesn't use(directly import) core-js-pure to polyfill and then add it to the global?

IMO, this will greatly reduce the duplications because at now many libs usally use @babel/transform-runtime with { corejs: 3}(finally is core-js-pure) but many apps use preset-env with {corejs: 2} (finally is core-js), there is no shared/shareable codes between apps and libs, right?

Refer to babel/babel#11515

[NE-SmallTown]

@slowcheetah @zloirock Hi, would you mind take a look at this? Thanks~

[zloirock]

It's a good issue.

core-js/modules/es.promise.js and core-js-pure/modules/es.promise.js are exactly the same code

They rely on modules with the same name, but with a different code.

Could we import the "pure" implementation and set it to global for global polyfill?

The "pure" implementation has too many limitations, uses expensive workarounds, in many cases non-complete, so we could not do it.

I played with solving this problem for a long time. Sharing common modules between those versions makes no sense - it's just a little part of the code size and it will increase the size of each version if it's used alone.

However, now I have an idea of how to solve this issue in the next generation of tools. The details will be later.

[NE-SmallTown]

Ah, happy to wait for your 'The details'

[zloirock]

I wanted to publish details a long time ago, but I posted this only right now. This problem should be solved in this, transpiler-based, way.