0.29.2 breaks webpack build

[m-mohr]

Since 0.29.2 I'm getting the following error when building a Vue component that uses commonmark.js:

"export 'default' (imported as 'commonmark') was not found in 'commonmark'

Im importing with import commonmark from 'commonmark';.

I'm building with vue-cli and that uses webpack again. I suspect that #186 broke it, at least I can make it work by downgrading to 0.29.1.

[jgm]

See the discussion in #136.

I'm sorry about this; I don't use JavaScript myself and I'm not up on the module technology. As far as I could tell, #136 was doing the right thing, but maybe not. It may work to do import * as commonmark from 'commonmark', as suggested in the discussion there. But it may be that we are doing things in a non-standard way that violates expectations (and creates problems with backwards-compatibility). IN that case, I'd like to fix it, but I'll need help from people who know what they're doing with JS modules.

[m-mohr]

Thank you, I'm also not really into all the details about JS modules.

I guess it would help to add to the readme how to include the library. I guess most people would try import commonmark from 'commonmark' instead of import * as commonmark from 'commonmark'. For me it seems that the default export is missing and should be added. Anyway, the proposed solution works for now, but as it's a breaking change (I think), it might be a good idea to fix things in 0.29.3.

[jgm]

Sure. How do I fix it so that import commonmark from 'commonmark' works again?
And, will that break import * as commonmark from 'commonmark'?

[m-mohr]

Again, I'm not an expert and haven't checked it, but I'd assume something like that should work in index.js:

import Node from "./node.js"
import Parser from "./blocks.js";
import Renderer from "./render/renderer.js";
import HtmlRenderer from "./render/html.js";
import XmlRenderer from "./render/xml.js";

const lib = { Node, Parser, Renderer, HtmlRenderer, XmlRenderer };
export lib; // makes `import * as commonmark from 'commonmark'` work
export default lib; // makes `import commonmark from 'commonmark'` work

But better let other experts double check that this works.

[hp4k1h5]

not an expert but this is my understanding as well, at least for node 14.11+

export lib; // makes import * as commonmark from 'commonmark' work
export default lib;

this export setup should provide the two import styles, as well as

import { lib } from './lib.js' // same as import * as lib from './lib.js'

[jgm]

So, is this the normal thing to do, making both styles of import work?

[m-mohr]

No, usually I'd only expect the export default thing that allows me to do import commonmark from 'commonmark'. I've not seen many libraries do import * as commonmark from 'commonmark'. Anyway, 0.29.2 introduced it and some people adopted, so to not break things again it seems it must support both from now on?!

[jgm]

For some reason export lib didn't work. I had to use a constant there instead.
But I've adopted this suggestion.

I'm not sure about whether to continue supporting import * as commonmark, but we should probably at least support it in the next release, with a deprecation notice.

[jgm]

OK, having both styles seems to be a problem:
https://github.com/commonmark/commonmark.js/runs/1166893414?check_suite_focus=true
I think I'll just go to the preferred style and people will have to deal with the breakage.
Fortunately 0.29.2 was very recently released, so I hope it won't affect too many people.

[jgm]

Actually, I'm going to reopen this and try to get more feedback.
I see that some libraries use one style (e.g. entities), while others use the other.
I'm not sure what is best, but supporting both seems to be impossible.
Advice welcome from people who know more about this than I do!

[jgm]

I've reverted the changes related to this issue, for now.

[jgm]

This should be fixed by #203

[MartinX3]

I'm still getting "export 'default' (imported as 'commonmark') was not found in 'commonmark' with 0.29.3 in vueJS 2.x
Or I understand the PR wrong