# Step 18 — Phase 6.1: 构建脚本

**依赖**: Step 15（extension.ts 完成）  
**参考设计**: §15

## 目标

搭建 esbuild 构建流程，替换 tsc 为打包构建，更新 package.json 脚本。

## 文件变更

| # | 文件 | 操作 | 说明 |
|---|------|------|------|
| 1 | `scripts/build.mjs` | 新建 | esbuild 打包脚本 |
| 2 | `package.json` | 修改 | 更新 build/vscode:prepublish 脚本 |

## 前置准备

```bash
npm install --save-dev esbuild@^0.28.1
```

---

## 1. `scripts/build.mjs`

```javascript
import * as esbuild from 'esbuild';
import { copyFileSync, mkdirSync, existsSync, cpSync } from 'fs';
import { resolve, dirname } from 'path';
import { fileURLToPath } from 'url';

const __dirname = dirname(fileURLToPath(import.meta.url));
const rootDir = resolve(__dirname, '..');
const outDir = resolve(rootDir, 'out');

if (!existsSync(outDir)) {
  mkdirSync(outDir, { recursive: true });
}

await esbuild.build({
  entryPoints: [resolve(rootDir, 'src', 'extension.ts')],
  bundle: true,
  outfile: resolve(outDir, 'extension.js'),
  external: [
    'vscode',
    'eslint',
    'stylelint',
    'child_process',
    'fs',
    'path',
    'url',
    'os',
  ],
  format: 'cjs',
  platform: 'node',
  target: 'node22',
  minify: true,
  sourcemap: false,
  treeShaking: true,
});

const jarsSrc = resolve(rootDir, 'jars');
const jarsDest = resolve(outDir, 'jars');
if (existsSync(jarsSrc)) {
  cpSync(jarsSrc, jarsDest, { recursive: true, force: true });
}

console.log('Build complete.');
```

---

## 2. `package.json` 脚本更新

```json
{
  "scripts": {
    "compile": "tsc -p ./",
    "watch": "tsc -watch -p ./",
    "build": "node scripts/build.mjs",
    "vscode:prepublish": "npm run build",
    "pretest": "npm run compile && npm run lint",
    "lint": "eslint src",
    "test": "vscode-test"
  }
}
```

---

## 关键逻辑

- `external`: vscode API、npm 包、Node 内置模块不打包
- `format: 'cjs'`: VSCode 扩展需要 CommonJS
- `target: 'node22'`: 对应 VSCode 1.120+ 的 Node 版本
- `minify: true`: 产物压缩
- `treeShaking: true`: 移除未使用代码
- 复制 `jars/` 目录到 `out/` 供运行时加载
- `vscode:prepublish` 改为 `npm run build`（生产打包）

---

## 验收

- [ ] `npm run build` 成功执行
- [ ] `out/extension.js` 生成（单文件 bundle）
- [ ] `out/jars/` 目录存在
- [ ] F5 启动扩展开发宿主功能正常