Add package metadata files and get tests running

.eslintignore

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+build/
+dist/
+**/*.js

.eslintrc

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+{
+  "extends": "./node_modules/gts/",
+  "rules": {
+    "@typescript-eslint/explicit-function-return-type": [
+      "error",
+      {"allowExpressions": true}
+    ],
+    "func-style": ["error", "declaration"],
+    "prefer-const": ["error", {"destructuring": "all"}],
+    // It would be nice to sort import declaration order as well, but that's not
+    // autofixable and it's not worth the effort of handling manually.
+    "sort-imports": ["error", {"ignoreDeclarationSort": true}],
+  }
+}

.github/dependabot.yml

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+version: 2
+updates:
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"

.github/workflows/ci.yml

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+name: CI
+
+defaults:
+  run: {shell: bash}
+
+env:
+  PROTOC_VERSION: 3.x
+
+on:
+  push:
+    branches: [main, feature.*]
+    tags: ['**']
+  pull_request:
+
+jobs:
+  static_analysis:
+    name: Static analysis
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 'lts/*'
+          check-latest: true
+      - run: npm install
+      - run: npm run check
+
+  tests:
+    name: 'Tests | Node ${{ matrix.node-version }} | ${{ matrix.os }}'
+    runs-on: ${{ matrix.os }}-latest
+
+    strategy:
+      matrix:
+        os: [ubuntu, macos, windows]
+        node-version: ['lts/*', 'lts/-1', 'lts/-2']
+      fail-fast: false
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+          check-latest: true
+      - run: npm install
+      - run: npm run test
+
+  deploy:
+    name: Deploy
+    runs-on: ubuntu-latest
+    if: "startsWith(github.ref, 'refs/tags/') && github.repository == 'sass/sync-process'"
+    needs: [static_analysis, tests]
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 'lts/*'
+          check-latest: true
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm install
+      - run: npm publish
+        env:
+          NODE_AUTH_TOKEN: '${{ secrets.NPM_TOKEN }}'
+
+  typedoc:
+    runs-on: ubuntu-latest
+    if: "startsWith(github.ref, 'refs/tags/') && github.repository == 'sass/sync-process'"
+    needs: [deploy]
+
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+
+    permissions:
+      pages: write
+      id-token: write
+
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 'lts/*'
+          check-latest: true
+          registry-url: 'https://registry.npmjs.org'
+      - run: npm install
+      - run: npm run doc
+
+      - name: Upload static files as artifact
+        uses: actions/upload-pages-artifact@v3
+        with: {path: docs}
+
+      - id: deployment
+        uses: actions/deploy-pages@v4

.gitignore

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+.DS_Store
+build
+dist
+node_modules
+npm-debug.log*
+package-lock.json
+
+# Editors
+.idea
+.vscode
+*.njsproj
+*.ntvs*
+*.sln
+*.suo
+*.sw?

.prettierrc.js

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+module.exports = {
+  ...require('gts/.prettierrc.json'),
+};

CODE_OF_CONDUCT.md

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+Sass is more than a technology; Sass is driven by the community of individuals
+that power its development and use every day. As a community, we want to embrace
+the very differences that have made our collaboration so powerful, and work
+together to provide the best environment for learning, growing, and sharing of
+ideas. It is imperative that we keep Sass a fun, welcoming, challenging, and
+fair place to play.
+
+[The full community guidelines can be found on the Sass website.][link]
+
+[link]: http://sass-lang.com/community-guidelines

CONTRIBUTING.md

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+# How to Contribute
+
+We'd love to accept your patches and contributions to this project. There are
+just a few small guidelines you need to follow.
+
+* [Contributor License Agreement](#contributor-license-agreement)
+* [Code Reviews](#code-reviews)
+* [Large Language Models](#large-language-models)
+
+## Contributor License Agreement
+
+Contributions to this project must be accompanied by a Contributor License
+Agreement. You (or your employer) retain the copyright to your contribution;
+this simply gives us permission to use and redistribute your contributions as
+part of the project. Head over to <https://cla.developers.google.com/> to see
+your current agreements on file or to sign a new one.
+
+You generally only need to submit a CLA once, so if you've already submitted one
+(even if it was for a different project), you probably don't need to do it
+again.
+
+## Code Reviews
+
+All submissions, including submissions by project members, require review. We
+use GitHub pull requests for this purpose. Consult
+[GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
+information on using pull requests.
+
+## Large Language Models
+
+Do not submit any code or prose written or modified by large language models or
+"artificial intelligence" such as GitHub Copilot or ChatGPT to this project.
+These tools produce code that looks plausible, which means that not only is it
+likely to contain bugs those bugs are likely to be difficult to notice on
+review. In addition, because these models were trained indiscriminately and
+non-consensually on open-source code with a variety of licenses, it's not
+obvious that we have the moral or legal right to redistribute code they
+generate.

LICENSE

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+Copyright (c) 2024, Google LLC
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.md

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+# `sync-process`
+
+This package exposes a `SyncProcess` class that allows Node.js to run
+a subprocess synchronously *and* interactively.
+
+## Usage
+
+Use `new SyncProcess()` to start running a subprocess. This supports the same
+API as [`child_process.spawn()`] other than a few options. You can send input to
+the process using `process.stdin`, and receive events from it (stdout, stderr,
+or exit) using `process.next()`. This implements [the iterator protocol], but
+*not* the iterable protocol because it's intrinsically stateful.
+
+[the iterator protocol]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Iteration_protocols#the_iterator_protocol
+[`child_process.spawn()`]: https://nodejs.org/api/child_process.html#child_processspawncommand-args-options
+
+```js
+import {SyncProcess} from 'sync-process';
+// or
+// const {SyncProcess} = require('sync-process');
+
+const node = new SyncProcess('node', ['--interactive']);
+
+for (;;) {
+  if (node.next().value.data.toString().endsWith('> ')) break;
+}
+
+node.stdin.write("41 * Math.pow(2, 5)\n");
+console.log((node.next().value.data.toString().split("\n")[0]));
+node.stdin.write(".exit\n");
+console.log(`Node exited with exit code ${node.next().value.code}`);
+```
+
+## Why synchrony?
+
+See [the `sync-message-port` documentation] for an explanation of why running
+code synchronously can be valuable even in an asynchronous ecosystem like
+Node.js
+
+[the `sync-message-port` documentation]: https://github.com/sass/sync-message-port?tab=readme-ov-file#why-synchrony
+
+### Why not `child_process.spawnSync()`?
+
+Although Node's built-in [`child_process.spawnSync()`] function does run
+synchronously, it's not interactive. It only returns once the process has run to
+completion and exited, which means it's not suitable for any long-lived
+subprocess that interleaves sending and receiving data, such as when using the
+[embedded Sass protocol].
+
+[`child_process.spawnSync()`]: https://nodejs.org/api/child_process.html#child_processspawnsynccommand-args-options
+[embedded Sass protocol]: https://github.com/sass/sass/blob/main/spec/embedded-protocol.md
+
+---
+
+Disclaimer: this is not an official Google product.

jest.config.ts

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+const config = {
+  roots: ['<rootDir>/lib/'],
+  preset: 'ts-jest',
+  testEnvironment: 'node',
+};
+
+export default config;