NodeJS's __filename/__dirname in ES6 Modules

Andrea Giammarchi andrea.giammarchi at gmail.com
Sat Jan 21 17:49:05 UTC 2017


FWIW I have both `__filename` and `__dirname` implemented in common-js
package runtime, and these are resolved as absolute path from the root,
unless imported externally where these are resolved as absolute URLs.

Although I must say beside providing some debuggable information, without a
core path module I don't see much added value in having these two
references.

I still load relatively via `module.import('./lib')` or
`module.import('../js/file')`

Regards



On Sat, Jan 21, 2017 at 5:02 PM, Bradley Meck <bradley.meck at gmail.com>
wrote:

> Please see https://github.com/tc39/proposal-dynamic-import#an-
> actual-function
>
> As per `"currentDir()" and "currentFile()"` this may not make sense for
> all URLs. Please use https://url.spec.whatwg.org/ which ships in Node v7+
> under `require('url').URL` and the proposal to bring it into the language
> itself https://github.com/jasnell/proposal-url . Getting the "directory"
> of a URL would be ~= `new URL('.', file_url)`.
>
> On Sat, Jan 21, 2017 at 10:42 AM, Gil Tayar <gil at tayar.org> wrote:
>
>> Thanks!
>>
>> Makes total sense. So why not have Domenic's "import" be a real function
>> that comes from this "js:context", thus obviating the need for a new
>> JavaScript operator?
>>
>> While I realize that "js:context" will a Node thing, we could have a
>> special import (e.g. import {...} from "js:system") that enables the system
>> to expose real functions, of which one is "dynamicImport" and others would
>> be "currentDir()" and "currentFile()".
>>
>> In other words - Domenic exposed a real need, but it seems that this need
>> is more general, and not specific only to dynamic import, and should be
>> added to the spec as a special import, just like it may be in Node.
>>
>>
>> On Fri, Jan 20, 2017 at 6:48 PM Bradley Meck <bradley.meck at gmail.com>
>> wrote:
>>
>>> The current trend is towards the https://github.com/nodejs/
>>> node-eps/pull/39 rewrite which does not have magic variables
>>> https://github.com/bmeck/node-eps/blob/b14276ca093
>>> fac9cbc3b72ff5433df35ae67fb59/002-es-modules.md#341-
>>> environment-variables
>>>
>>> There are ideas about exposing the URL of the current ESM via something
>>> like https://docs.google.com/presentation/d/1aq_QjBUQTovj9aQ
>>> ZQrVzS7l1aiOs3ZNlk7wgNTUEMy0/edit#slide=id.g16ab11d101_0_22
>>>
>>> On Fri, Jan 20, 2017 at 10:42 AM, Gil Tayar <gil at tayar.org> wrote:
>>>
>>> While reading Dominic Denicola's spec for dynamic import() at
>>> https://github.com/tc39/proposal-dynamic-import, I read his rational
>>> for not having import be a regular function, but rather a "syntactic form".
>>> The idea is that import() needs to be "in the scope" of the current module,
>>> as it needs to resolve the module path it is given relative to the current
>>> module's.
>>> Thinking about it some more, I thought it would be a pity for import to
>>> be so "special", and asked myself whether there will be more features that
>>> will need to be "module-aware" like import().
>>>
>>> And there are! (I think...) - __filename and __dirname in NodeJS are
>>> exactly such features. Actually, anything passed to the function wrapping
>>> each NodeJS module is such a feature, but going over them, only __filename
>>> and __dirname are not immediately related to the module mechanism.
>>>
>>> So my question is this (and it is specifically addressed to the NodeJS
>>> implementors in the group): in NodeJS's implementation of ES6 modules, how
>>> will __dirname and __filename be implemented? Will there still be a
>>> function wrapper like in the current module implementation? Or will
>>> __dirname and __filename be a "syntactic form" like import()? Or something
>>> else?
>>>
>>> Thanks,
>>> Gil Tayar
>>>
>>> _______________________________________________
>>> es-discuss mailing list
>>> es-discuss at mozilla.org
>>> https://mail.mozilla.org/listinfo/es-discuss
>>>
>>>
>>>
>
> _______________________________________________
> es-discuss mailing list
> es-discuss at mozilla.org
> https://mail.mozilla.org/listinfo/es-discuss
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.mozilla.org/pipermail/es-discuss/attachments/20170121/545ca72f/attachment-0001.html>


More information about the es-discuss mailing list