bindings/node: add Conversation.createExternalInvite NAPI binding

[tylerhawkes]

Summary

NAPI binding for MlsGroup::create_external_invite (PR-L10).

• New file bindings/node/src/conversation/external_invite.rs.
• Buffer in, Buffer out — no encoding conversions at the boundary. The caller's TS/JS code chooses how to transport the invite payload bytes (hex, base64, raw QR encoder, ...).

Stack

• Base: tyler/qr-invite-l10-create-invite (xmtp_mls: MlsGroup::create_external_invite (produce QR-invite payload + encrypted GroupInfo) #3673).
• Pair: PR-B2 (joinGroupByExternalInvite binding).

Test plan

• cargo check -p bindings_node passes.
• node-side smoke test (will land with B-2 or T-1 once the full flow is wired).

Note

Add Conversation.createExternalInvite NAPI binding to node bindings

• Adds a new async createExternalInvite method to Conversation in external_invite.rs, accepting optional servicePointer (bytes) and expiresAtNs (bigint) options.
• Returns a CreateExternalInviteOutput object with invitePayload and encryptedGroupInfo as Uint8Array values, converted from the underlying MLS group call.
• Validates expiresAtNs: throws a napi error if the value is negative or exceeds u64 range.
• Exports the new module via mod.rs.

^{Macroscope summarized df2c7b6.}

[claude]

Claude finished @tylerhawkes's task —— View job

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PR Review Complete ✓

Reviewed at: 2026-05-27 18:34 UTC

Summary

Clean, well-structured NAPI binding that correctly wraps the underlying Rust functionality. The code follows existing patterns in the codebase and includes appropriate validation. No significant issues found.

Minor Observations

1. BigInt validation (bindings/node/src/conversation/external_invite.rs:62-72)

   • The validation logic correctly handles negative values and overflow
   • Consider extracting this pattern into a helper if similar BigInt→u64 conversions appear elsewhere in the codebase (not required for this PR)

2. Test coverage

   • Author correctly notes that node-side integration tests will land with B-2/T-1
   • The underlying Rust implementation has unit tests (xmtp_mls/src/groups/external_invite.rs:203-274)
   • NAPI binding layer is straightforward type conversion; comprehensive testing makes more sense at the integration level

3. Code consistency

   • Follows established patterns (e.g., create_mls_group(), ErrorWrapper::from, async/Result signatures)
   • Struct documentation clearly explains the boundary contract (buffer in, buffer out)
   • Export in mod.rs:12 properly integrates the new module

Verdict

✅ Approve — no blocking issues. The binding is a thin, correct wrapper with appropriate validation.

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[macroscopeapp]

Approvability

Verdict: Approved

This PR adds a Node.js binding that wraps existing Rust functionality for creating external invites. The changes are self-contained, involve straightforward type conversions, and the author owns all modified files.

No code changes detected at df2c7b6. Prior analysis still applies.

^{You can customize Macroscope's approvability policy. Learn more.}

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (tyler/qr-invite-l10-create-invite@e8978a2). Learn more about missing BASE report.

Additional details and impacted files

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Dismissing prior approval to re-evaluate 9c190fa