CODEWITHSUNDEEP
google-closure-compiler
Alvaro Fuentes Zurita
Alvaro Fuentes Zurita

Reputation: 434

Node.js externs for closure compiler?

Firstly: The "official" (?) node.js externs are located here: https://github.com/google/closure-compiler/tree/master/contrib/nodejs

But i can't use it because the high amount of warnings (and errors sometimes) that are generated. For example: The declaration of "process" module is very "thin"; Only has one property defined on his prototype, besides not inherit from EventEmitter, so i can't register callback when, for example, i want to do a clean job on process SIGINT (process.on('SIGINT', callback)).

When i mix several externs files declaring the core modules of node.js, more and more warnings and errors are raised (i always respect the deps tree between externs). For example: If i include the events.js and stream.js externs files, an error is raised because the "event" global var is redeclared: Once in events and again in stream.

So: What am i doing wrong?

The closure compiler that i am using is the latest git, whit --new_type_inf and --env flags activated, among others.

Upvotes: 1

Views: 590

Answers (1)

Chad Killingsworth
Chad Killingsworth

Reputation: 14411

For example: If i include the events.js and stream.js externs files, an error is raised because the "event" global var is redeclared: Once in events and again in stream.

This highlights the core of the problem - and why they are not well maintained. The compiler doesn't recognize that these variables are in fact NOT global. The compiler currently does not have a method to correctly interpret externs as modules. The were originally contributed and consumed by a fork of the project that could understand externs as modules.

I am currently working on adding support to the compiler for this and hope to some day soon be able to completely rewrite this answer.

In the mean time, you might be able to work around some of this by adding @suppress {duplicate} annotations to the files. However keep in mind that they will still be global types.

If you wish to improve the files (like having process properly extend EventEmitter), I will happily review pull requests for such changes.

Upvotes: 2

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