Do not depend on environmental typings?

[blakeembrey]

I think I've brought this up a few times privately now, but I recently saw microsoft/TypeScript#10250 and thought I should bring it up publicly now. Having a dependency on an environment that does not exist can be bad and easily introduces numerous bugs. The most prolific is when DefinitelyTyped started introducing global Promise typings when you may have been running on node 0.10 which does not have promises. However, the same thing can exist else - for instance, using or exposing a specific method from http.Request or Buffer, etc. can create subtle bugs in the runtime while compile time tells you everything is good.

[felixfbecker]

The whole pattern of adding the global node declaration as a dependency (not peerDependency) is the cause of this issue. See this build for example: https://travis-ci.org/felixfbecker/merkel/builds/166880677
typedoc switched over to @types in a minor release. typedoc itself only depends on @types/fs-extra and a couple other modules. So far so good, but @types/fs-extra has a dependency on @types/node@*. Which is a global declaration. But I already have node typings installed (through typings), so now I get duplicate identifier errors and my build is broken through a minor version update, and typedoc is not even to blame here because it didn't even depend on @types/node directly. It would have all been fine if @types/fs-extra declared a peerDependency.

#173 (comment)

[blakeembrey]

Is there a chance of a response on this? Does DefinitelyTyped support peer dependencies for this at all? These changes just broke the one of the few packages I maintain that actually uses @types (e.g. TypeStrong/typedoc#444 (comment), broken from a definition that has a direct dependency on node instead of a peer dependency - using a peer dependency would have meant I would have known this transitive oddity from the beginning).

[scottmtraver]

Following

I am having a similar problem. Resulting from Protractor version 5.1.1 using @types/node but we already have node typings from typings.json.

[WorldMaker]

I was definitely bit by this as well. @types/lodash wants to work whether or not some globals are defined (WeakMap being one) and so uses global module augmentation with an empty version of the interface to handle that, but that broke when lib.d.ts changes the type signature of those globals between TS versions. Moving that to a peerDependency might help. Using something more flexible than module augmentation might help.