stream: expose stream symbols

[ronag]

This is required for streams interop with e.g. readable-stream. Currently readable-stream helpers will not work with normal node streams which is confusing and bad for the ecosystem.

[nodejs-github-bot]

Review requested:

• @nodejs/streams

[aduh95]

If we expose them, we would need to document them. I don't think we want to do that, making symbols part of the public API goes against the idea of using symbols. Can't readable-stream use Reflect.ownKeys or Object.getOwnPropertySymbols to achieve that?

[ronag]

How would it do that? I'm not sure how that would work. Especially in a performant way.

[ErickWendel]

How would it do that?

constkKey=Symbol('key')classMy{[kKey](){console.log('hello')}}const[,symKey]=Reflect.ownKeys(My.prototype)newMy()[symKey]()// hello

[ronag]

How would it do that?

constkKey=Symbol('key')classMy{[kKey](){console.log('hello')}}const[,symKey]=Reflect.ownKeys(My.prototype)newMy()[symKey]()// hello

The symbols are not an a prototype...

[ErickWendel]

How would it do that?

constkKey=Symbol('key')classMy{[kKey](){console.log('hello')}}const[,symKey]=Reflect.ownKeys(My.prototype)newMy()[symKey]()// hello

The symbols are not an a prototype...

They also work in objects, don't they?

constobj={[Symbol("test")]: 'hey'}const[symbol]=Reflect.ownKeys(obj)console.log(obj[symbol])// hey

For Streams:

conststr=stream.Readable.from('abc')constdata=Reflect.ownKeys(str)constkCapture=data[6]str[kCapture]// false

[ronag]

I still don't see how that will work. Would need to know the static index of the symbol. Which is not possible atm.

[vweevers]

This case is similar to Symbol.for('nodejs.util.inspect.custom') in its goal to improve portability. How about using global symbols, e.g. Symbol.for('nodejs.stream.destroyed')? The intent would be clearer, compared to exporting symbols.

[RaisinTen]

Why don't we use a regular string key to expose these values like what was done in the case of readable.closed and document that instead? That way, we won't be exposing raw non-global symbols, which aren't meant to be a part of the public API and there would also be no need to use Reflect.ownKeys or Object.getOwnPropertySymbols.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/48247/

[ronag]

@nodejs/streams some reviews?

[ronag]

@mcollina We will need this in readable-stream for proper interop.

[aduh95]

Adding the tsc-agendaIssues and PRs to discuss during the meetings of the TSC. so we can discuss how to expose internals and what should be the adequate documentation / semver expectations around it.

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/50404/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/50439/

[nodejs-github-bot]

CI: https://ci.nodejs.org/job/node-test-pull-request/50444/

[nodejs-github-bot]

Landed in 8c60add

[anonrig]

Note: I believe this change requires an update to the documentation as well.

[ronag]

Note: I believe this change requires an update to the documentation as well.

This is not intended as a public api.