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• ✅ login: GuilleX7 / name: Guillermo (74161a0)

We have a microfrontend that we load using Module Federation and we want to have multiple instances of it running at the same time. The problem is that it uses singleton libraries, so mounting it twice is not enough, as the runtime would be the same and both would share the same instance.

What we are doing right now is to run remoteEntry multiple times, creating different runtimes so multiple instances of the library are instantiated. However, with this approach we only get HMR in the latest instance that has been created.

So you mean that we would be getting the same instance of the module for both instances over HMR? I wasn't aware of this limitation. Do you think there might be another approach that we are ignoring?

So you mean that we would be getting the same instance of the module for both instances over HMR? I wasn't aware of this limitation. Do you think there might be another approach that we are ignoring?

Yes, to solve this you need to give a unique name - https://webpack.js.org/configuration/output/#outputuniquename

The problem is that we couldn't find any way to make the uniqueName (and thus the JSONP loaders) dynamic. We need to compile the microfrontend once and run it multiple times within the same window context, but the chunk loaders and the HMR loaders seem to have a fixed name always.

Is there anything like a wrapper of the entrypoint that allows to set a unique name before actually executing the runtime and attaching the JSONP loaders?

Edit: also, I've been thinking about the same instance of the module being reused by both runtimes. Is it really like that? I might be completely wrong here, but doesn't the HMR chunk update contains module factories? My guess is that we are just passing the module factories to each runtime and that they will instantiate different modules, isn't it?

I just made a small test by using Math.random() as the value of the hot-replaced module, and seems to be called twice:

The problem is that we couldn't find any way to make the uniqueName (and thus the JSONP loaders) dynamic. We need to compile the microfrontend once and run it multiple times within the same window context, but the chunk loaders and the HMR loaders seem to have a fixed name always.

Is there anything like a wrapper of the entrypoint that allows to set a unique name before actually executing the runtime and attaching the JSONP loaders?

it is impossible, you can't have multiple on the same page, we don't support bidirectional multiple HMR, it is very hard task, yes it can work in some cases, but I would strictly say that this is not the best idea

Also this fix handle only jsonp, but we have more types

Edit: also, I've been thinking about the same instance of the module being reused by both runtimes. Is it really like that? I might be completely wrong here, but doesn't the HMR chunk update contains module factories? My guess is that we are just passing the module factories to each runtime and that they will instantiate different modules, isn't it?

Because it is a simple case, in the real world you can have multiple async chunks and in some you can have module in some not.

I would say you need to rethink your architecture.

You can look at our source code and see:

F(output, "hotUpdateGlobal", () => `webpackHotUpdate${uniqueNameId}`);

Based on your changes I assume you overridden it or don't provide a value at all, that is why you faced with it, I can provide more feedback if you provide small reproducible example.