[nodemailer] Remove AWS SDK from dependencies, use structural types

[benjaminpjones]

Move @aws-sdk/client-sesv2 (v7) and @aws-sdk/client-ses (v6) from dependencies to devDependencies so users who install @types/nodemailer don't pull in the large AWS SDK dependency tree.

Replace AWS SDK type imports with structural "like" types that match the shape nodemailer actually needs. This works because TypeScript uses structural typing - the real AWS SDK types will still be accepted when users install the SDK themselves for SES transport.

Fixes discussion #74080

Note: this is largely in line with how nodemailer itself treats aws-sdk - it's not a direct dep. See docs:

The AWS SES SDK is not included with Nodemailer, so you need to install it separately:
npm install @aws-sdk/client-sesv2

---

Template:

• Use a meaningful title for the pull request. Include the name of the package modified.
• Test the change in your own code. (Compile and run.)
  • N/A - my code doesn't use the ses bits
• Add or edit tests to reflect the change.
  • I didn't add tests, but I kept the existing ones the same to ensure these are still compatible with the AWS lib
• Follow the advice from the readme.
• Avoid common mistakes.
• Run pnpm test nodemailer.

Changing an existing definition:

• Provide a URL to documentation or source code which provides context for the suggested changes: [@types/nodemailer] should not package `@aws-sdk/client-sesv2` #74080
• If this PR brings the type definitions up to date with a new version of the JS library, update the version number in the package.json. (N/A)

[typescript-bot]

@benjaminpjones Thank you for submitting this PR! I see this is your first time submitting to DefinitelyTyped 👋 — I'm the local bot who will help you through the process of getting things through.

This is a live comment that I will keep updated.

1 package in this PR

• nodemailer — on npm, on unpkg

Code Reviews

Because this is a widely-used package, a DT maintainer will need to review it before it can be merged.

You can test the changes of this PR in the Playground.

Status

• ✅ No merge conflicts
• ✅ Continuous integration tests have passed
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All of the items on the list are green. To merge, you need to post a comment including the string "Ready to merge" to bring in your changes.

---

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[typescript-bot]

Hey @benjaminpjones,

😒 Your PR doesn't modify any tests, so it's hard to know what's being fixed, and your changes might regress in the future. Please consider adding tests to cover the change you're making. Including tests allows this PR to be merged by yourself and the owners of this module.

This can potentially save days of time for you!

[typescript-bot]

🔔 @rogierschouten @dex4er @bioball — please review this PR in the next few days. Be sure to explicitly select Approve or Request Changes in the GitHub UI so I know what's going on.

[benjaminpjones]

😒 Your PR doesn't modify any tests, so it's hard to know what's being fixed, and your changes might regress in the future. Please consider adding tests to cover the change you're making. Including tests allows this PR to be merged by yourself and the owners of this module.

This PR fixes dependency bloat - there's not a great test for it. I did intentionally leave existing tests the same so to ensure this is still compatible with the aws-sdk types.

[typescript-bot]

Re-ping @rogierschouten, @dex4er, @bioball:

This PR has been out for over a week, yet I haven't seen any reviews.

Could someone please give it some attention? Thanks!

[typescript-bot]

It has been more than two weeks and this PR still has no reviews.

I'll bump it to the DT maintainer queue. Thank you for your patience, @benjaminpjones.

(Ping @rogierschouten, @dex4er, @bioball.)

[jakebailey]

Do you have a way to cross reference the types here to what nodemailer uses under the hood?

[benjaminpjones]

@jakebailey thank you for taking a look.

Do you have a way to cross reference the types here to what nodemailer uses under the hood?

I took a second pass at manually cross-referencing against the nodemailer source, a couple changes:

• v7 (SESv2): lib/ses-transport/index.js - uses this.ses.sesClient.send(command), new this.ses.SendEmailCommand(sesMessage), and this.ses.sesClient.config.region() for region detection
• v6: lib/ses-transport/index.js @ v6.9.16 - uses ses.send(new aws.SendRawEmailCommand(sesMessage)) for v3 API or ses.sendRawEmail(sesMessage).promise() for v2 API

There's no automated way to verify these structural types match. Is there a standard approach in DT for cross-referencing structural types against an underlying implementation? Or is manual review the expectation here?

[weswigham]

Yeah, manual review to ensure it matches the package's internal uses is all you can do if you're looking to structurally match those uses. Means the types might shift based on minor/internal changes, or you loosen them a bunch, but that's not so bad.

[typescript-bot]

@benjaminpjones: Everything looks good here. I am ready to merge this PR (at 3519f3c) on your behalf whenever you think it's ready.

If you'd like that to happen, please post a comment saying:

Ready to merge

and I'll merge this PR almost instantly. Thanks for helping out! ❤️

(@rogierschouten, @dex4er, @bioball: you can do this too.)

[benjaminpjones]

Ready to merge