On Jan 28, 2014 12:14 AM, "John Barton" <johnjbar...@google.com> wrote: > > > > > On Mon, Jan 27, 2014 at 2:50 PM, Sam Tobin-Hochstadt <sa...@cs.indiana.edu> wrote: >> >> This is absolutely necessary for polyfilling. >> >> Imagine that some browser has an ok-but-not-complete implementation of >> the X library, but you want to use jQuery 17, which requires a better >> version. You need to be able to replace X with a polyfilled update to >> X, and then load jQuery on top of that. >> >> Note that this involves indirect access in the same library (jQuery) >> to two versions of X (the polyfill and the browser version), which is >> why I don't think Marius's worry is fixable without throwing out the >> baby with the bathwater. > > > Guy Bedford, based on experiences within the requirejs and commonjs worlds, has a much better solution for these scenarios. (It's also similar to how npm works). > > Your jQuery should depend upon the name X, but you Loader should map the name X when loaded by jQuery to the new version in Loader.normalize(). The table of name mappings can be configured at run time. > > For example, if some other code depends on X@1.6 and jQuery needs X@1.7, they each load exactly the version they need because the normalized module names embed the version number.
This seems to handle the scenario where two versions is wanted. This would probably also work in the scenario where a unique instance of the same version should be given to every module depending on it. This would be useful for unit tests, where a clean world is required for each tests. Or for unit test maybe a new realm should be used for each test. If a module is redefined with imperative code then an error should probably be thrown, or the promise could be rejected. But I don't think that would be good for DOM manipulation. If innerHTML is used to add a lot of markup and an existing module to the DOM, should an error be thrown? Should none of the other markup be added to the DOM? What would the error message look like to adequately indicate the source of the error? Marius Gundersen > > This is the proper solution, not one based on overwriting the module registry. To be sure, because of the overhead loading code on slow networks these kinds of multi-version scenarios are less attractive in the browser, but the fix is the adapt the code. > > Guy's project has a bit more: https://github.com/guybedford/systemjs > > jjb > >> >> >> Sam >> >> On Mon, Jan 27, 2014 at 5:45 PM, John Barton <johnjbar...@google.com> wrote: >> > What is the use case for allowing registration different modules under the >> > same name? IMO should be an error. >> > jjb >> > >> > >> > On Mon, Jan 27, 2014 at 2:32 PM, David Herman <dher...@mozilla.com> wrote: >> >> >> >> On Jan 27, 2014, at 2:18 PM, Marius Gundersen <gunder...@gmail.com> wrote: >> >> >> >> > So then there would be two versions of the same module, and a module >> >> > could get access to both these modules at the same time. For example, if >> >> > ModuleB, which depends on ModuleA is loaded and linked, and later ModuleA is >> >> > redefined, then ModuleC could depend on both ModuleB and ModueA, and would >> >> > get (indirect) access to two versions of ModuleA. Is this problem >> >> > preventable? >> >> >> >> It's important to be able to modify module registration for things like >> >> polyfilling. But that doesn't mean it's something people should do in >> >> general. Note that Jason only gave you an answer in the context of the basic >> >> module loader semantics; he didn't say what will happen in the HTML >> >> semantics. In particular, we can make it an error for there to be two >> >> definitions of the same module name in the same HTML, a la: >> >> >> >> <script type="module" name="jquery" src="jquery1.js"></script> >> >> <script type="module" name="jquery" src="jquery2.js"></script> >> >> >> >> I'm inclined to call that an error, and require imperative modifications >> >> of existing module registrations to use imperative code. >> >> >> >> Dave >> >> >> >> _______________________________________________ >> >> es-discuss mailing list >> >> es-discuss@mozilla.org >> >> https://mail.mozilla.org/listinfo/es-discuss >> > >> > >> > >> > _______________________________________________ >> > es-discuss mailing list >> > es-discuss@mozilla.org >> > https://mail.mozilla.org/listinfo/es-discuss >> > > _______________________________________________ > es-discuss mailing list > es-discuss@mozilla.org > https://mail.mozilla.org/listinfo/es-discuss >
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