feat(emails): add --react-file flag to emails send

[pcristin]

Summary

Adds support for --react-file in resend emails send (issue #73), similar to --html-file.

What changed

• Added --react-file <path> option to emails send
• Loads the file as a module and uses its default export as react payload
• Updated body validation to accept --react-file as a valid body source
• Updated command help/examples to include --react-file
• Updated README options, examples, and error-code descriptions
• Added tests for:
  • successful --react-file usage
  • error path when react file has no default export

Behavior details

• Body source precedence is now:
  • --react-file
  • --html-file
  • --html
  • --text
• --react-file load failures return file_read_error

Verification

• pnpm lint
• pnpm typecheck
• pnpm test tests/commands/emails/send.test.ts
• pnpm test
• pnpm build

All commands pass locally.

Issue

Closes #73

---

Summary by cubic

Adds --react-file to resend emails send to send a React-rendered template from a module’s default export. Updates CLI help/README and tests.

• New Features
  • Loads a React file as an ES module and uses its default export as the react payload; rejects component function defaults with file_read_error.
  • Body precedence: --react-file → --html-file → --html → --text.
  • Errors: load failures or missing default export → file_read_error; missing body → missing_body.
  • Help/README updated with examples and error codes; tests cover success, precedence, and error paths.

^{Written for commit 951b069. Summary will update on new commits.}

[cubic-dev-ai]

3 issues found across 3 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="README.md">

<violation number="1" location="README.md:233">
P2: The `--react-file` documentation is ambiguous about whether it expects a React component function or a rendered React element. The README states "Path to a React module (default export)" which suggests a component function export is valid. However, the Resend SDK's `react` field expects a `React.ReactNode` (rendered element), not a component function - the SDK docs explicitly show calling the component (`EmailTemplate({userName})`). The CLI implementation passes the module's default export directly to the SDK without rendering, so if users export a component function as described, it will cause runtime failures.</violation>
</file>

<file name="tests/commands/emails/send.test.ts">

<violation number="1" location="tests/commands/emails/send.test.ts:248">
P2: Missing test coverage for precedence when --react-file is combined with other body flags. The PR documents a precedence guarantee (`--react-file` > `--html-file` > `--html` > `--text`), but the test only exercises `--react-file` in isolation. Consider adding a test that provides multiple body flags to verify the documented precedence behavior is enforced.</violation>
</file>

<file name="src/commands/emails/send.ts">

<violation number="1" location="src/commands/emails/send.ts:93">
P1: `--react-file` loads a React component but passes it to Resend without converting it to a React element. Resend's `emails.send()` expects a rendered React element (JSX/ReactNode), not a component function/class. When users provide a typical React email file with `export default function Email() {...}`, the default export is the component constructor, which will cause Resend to fail or render incorrectly. The code should wrap `mod.default` with `React.createElement()` before returning to ensure a proper React element is passed to the API.</violation>
</file>

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[pcristin]

@zenorocha please, review the PR

[felipefreitag]

Hi, thanks for the PR. It doesn't seem to work with a React Email template file.

I tested the implementation, and there's a gap between what users would expect and what --react-file currently accepts. React Email templates are .tsx component functions:

 export default function Welcome() {
    return <Html><Text>Hello</Text></Html>;
  }

But this PR expects a pre-built .mjs module whose default export is an already-rendered React element, not a component function. Users would need to compile and render the template themselves before passing it to the CLI

The original issue itself needs more thought.