fix(typescript): fix declaration file generation for single file outputs

[danimoh]

Rollup Plugin Name: typescript

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

If yes, then include "BREAKING CHANGES:" in the first commit message body, followed by a description of what is breaking.

List any relevant issue numbers:

Description

Previously, type declaration files were only emitted if outputOptions.dir was
used and not outputOptions.file or, as a side effect, if the tsconfig file was
specified via a qualified path. This commit fixes that, such that types are
also emitted for single file builds.

[shellscape]

Thanks for the PR. This looks good to me, nothing stands out of concern. Test looks good.

[trm217]

@shellscape FYI These changes seem to cause certain rollup-configs to break.
After the release of @rollup/plugin-typescript@8.3.4 the rollup-config below started failing.
The second compile task was no longer able to receive dist/types/index.d.ts which previous to v8.3.4 was emiited by the typescript-plugin in the first task.
From looking at the changes, I am unsure why this is happening, as declarationDir is explicitly defined in the tsconfig.

References

rollup.js config

import nodeResolve from '@rollup/plugin-node-resolve'
import commonjs from '@rollup/plugin-commonjs'
import peerDepsExternal from 'rollup-plugin-peer-deps-external'
import dts from 'rollup-plugin-dts'
import typescript from '@rollup/plugin-typescript'
import json from '@rollup/plugin-json'
import { terser } from 'rollup-plugin-terser'
import visualizer from 'rollup-plugin-visualizer'
import bundleSize from 'rollup-plugin-bundle-size'
import path from 'path'

const pkgJSON = require('./package.json')

export default [
  {
    input: 'src/index.ts',
    output: [
      {
        file: pkgJSON.module,
        format: 'esm',
      },
      {
        file: pkgJSON.main,
        format: 'cjs',
      },
    ],
    plugins: [
      peerDepsExternal(),
      nodeResolve(),
      json(),
      commonjs(),
      typescript({
        tsconfig: './tsconfig.json',
        outputToFilesystem: true,
      }),
      terser(),
      bundleSize(),
      process.env.ANALYZE === 'true' &&
        visualizer(() => ({
          filename: path.join(__dirname, 'bundle-analysis.html'),
        })),
    ],
    external: Object.keys(pkgJSON.peerDependencies || {}),
  },
  {
    input: 'dist/types/index.d.ts',
    output: [{ file: 'dist/index.d.ts', format: 'esm' }],
    plugins: [nodeResolve({ preferBuiltins: true }), dts()],
  },
]

tsconfig.json

{
  "compilerOptions": {
    "target": "ES5",
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "skipLibCheck": true,
    "strict": false,
    "forceConsistentCasingInFileNames": true,
    "esModuleInterop": true,
    "module": "ESNext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "jsx": "react-jsx",
    "incremental": true,
    "declaration": true,
    "declarationDir": "types",
    "rootDir": "src"
  },
  "include": [
    "src/**/*.ts",
    "src/**/*.tsx"
  ],
  "exclude": [
    "node_modules",
    "dist"
  ]
}

Additionally here is the package in which the issue occurred.

[vgpena]

I've been experiencing the same issue the same issue as @trm217. Our types have always been output into dist/types but with upgrading from 8.3.3 -> 8.3.4, now the types appear right in dist/. We edited our TS and Rollup configs a bit and were not able to find a clear cause, so we're pinning to v8.3.3 for now. Guidance is appreciated! 🙌🏻

Relevant config

Rollup.config.js (partial):

export default {
  input: 'src/index.ts',
  output: [
    {
      file: pkg.main,
      format: 'umd',
      sourcemap: true,
      name: 'index',
      globals,
    },
    {
      file: pkg.module,
      format: 'esm',
      sourcemap: true,
      name: 'index',
      globals,
    },
  ],
  plugins: [
    externals({
      deps: false,
    }),
    resolve({
      extensions: ['.js', '.jsx', '.ts', '.tsx'],
    }),
    commonjs({
      requireReturnsDefault: 'auto',
    }),
    typescript({
      tsconfig: './tsconfig.json',
      outputToFilesystem: true,
    }),
    json(),
  ],
}

tsconfig.json (complete):

{
  "compilerOptions": {
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "declaration": true,
    "declarationMap": false,
    "isolatedModules": true,
    "noFallthroughCasesInSwitch": true,
    "incremental": true,
    "baseUrl": "./src",
    "jsx": "react-jsx",
    "noEmit": false,
    "outDir": "dist",
    "declarationDir": "types",
  },
  "include": ["./src", "globals.d.ts"],
  "exclude": ["./**/*.js", "./**/*.jsx"]
}