Problem

Meteor's Rspack integration currently only supports .swcrc and swc.config.js for SWC transpiler configuration. TS developers can't use swc.config.ts for type-safe configs, which is a common pattern in modern TS projects.

Solution

Extended the SWC config loader to support .ts files:

• Added TS file handling with automatic transpilation (esbuild primary, regex fallback)
• Maintains priority order: .swcrc > swc.config.js > swc.config.ts
• Added swc.config.ts to Rspack cache dependencies for proper invalidation

Changes Made

npm-packages/meteor-rspack/lib/swc.js

• Extended getMeteorAppSwcrc() to handle .ts extensions
• Added TS transpilation with esbuild (falls back to regex if unavailable)
• Strips TS syntax: imports, types, interfaces, decorators
• Converts ES modules to CommonJS
• Updated getMeteorAppSwcConfig() to check for all three config types

npm-packages/meteor-rspack/rspack.config.js

• Added swc.config.ts path detection
• Included in build dependencies for cache invalidation

Verification

Tested with Meteor TS app:

• Only swc.config.ts present - loads correctly
• Both swc.config.js and swc.config.ts present - swc.config.js takes priority
• All three configs present - .swcrc takes priority

Example swc.config.ts:

import type { Config } from '@swc/core';

const config: Config = {
  jsc: {
    target: 'es2020',
    parser: {
      syntax: 'typescript',
      tsx: true,
      decorators: true,
    },
  },
  sourceMaps: true,
};

export default config;

Fixes #14033