SSR compiled modules expect to have access to @lwc/ssr-runtime

[lpomerleau]

Description

Steps to Reproduce

See lwc#2400 here.

In this PR, we are integrating the @lwc/ssr-compiler into LWR-Node for TD-0205202. We started passing TransformOptions.targetSSR = true into @lwc/compiler#transformSync.

1. Clone the lwr repo
2. Checkout the laura/ssr-compiler branch
3. yarn (install + build)
4. yarn ssr:start
5. Visit http://localhost:4000

Expected Results

The @lwc/ssr-runtime is found. It replaces the lwc imports during SSR compilation here.

Actual Results

The LWR-Node runtime cannot find the @lwc/ssr-runtime package when bundling an SSR-compiled LWC:

[error] 404: Could not find module entry with specifier "@lwc/ssr-runtime"

Note: this error may be buried under another error: https://github.com/salesforce/lwc/issues/4555

Browsers Affected

Node.js

Version

Node project package.json "peerDependencies": { "@lwc/compiler": ">= 2.x" } "devDependencies": { "@lwc/compiler": "7.2.6" }

• LWC: 7.2.6

Possible Solution

In LWR-Node, we set lwc as a peer dependency which is met by the app layer. Does the same approach need to be taken with @lwc/ssr-runtime to support SSR-compiled modules?

[nolanlawson]

So currently the lwc package does not export @lwc/ssr-compiler or @lwc/ssr-runtime. You can see its exported packages here: https://github.com/salesforce/lwc/tree/master/packages/lwc

I think we could definitely do this, but probably not until @lwc/ssr-* is ready for prime time.

In the meantime, yes, you would need to set it as a peer dependency. This is probably a good practice anyway, because transitive dependencies are not always allowed to be imported/required at the top level (I believe some versions of Yarn disallow this).

[nolanlawson]

Alternatively, we can just re-export these from the lwc package right now if this is a big blocker.