fix(Symbol.observable): make observable declaration readonly (#3697)

[scttcper]

rxjs symbol declaration creates error when combined with other packages

closes #3697

[david-driscoll]

@benlesh this may affect rxjs 5 as well, not sure if we want to patch it down that way or not.

[benlesh]

@david-driscoll this shouldn't affect RxJS 5 at all. if it does, it's because someone is doing something broken in TypeScript like assigning Symbol.observable = 'whatever'... if that's the case, they can just cast as any and fix. This is solving a bug, and isn't something we need to put off to another major version.

[benlesh]

Thank you, @scttcper!

[amaury1093]

Just to make sure: this isn't out yet in 6.2.0, correct?

Do you have an alpha version at par with master?

[paulstelzer]

@amaurymartiny It's not out yet and as you can see at https://www.npmjs.com/package/rxjs?activeTab=versions there is no new alpha or beta version. Just downgrade to @types/node@10.1.4 so everything is still working

[saeedkhan-github]

how to downgrad to @types/node@10.1.4 ?

[JohannesHoppe]

npm install @types/node@10.1.4

[paulstelzer]

rxjs@6.2.1 is online, so you do not need to downgrade @types/node - just update to the latest version of rxjs

[michelmob]

the same here. I'm using:

"rxjs": "^6.2.1",
"rxjs-compat": "^6.2.1",

and

"@types/node": "^10.1.4"

help?

Thanks!