feat: watch mode

Author: Sunny-117

build.config.ts

@@ -7,4 +7,13 @@ export default defineConfig({
       input: ['./src/index.ts', './src/cli.ts', './src/config.ts'],
     },
   ],
+  // Example watch configuration
+  watch: {
+    enabled: false, // Set to true to enable watch mode by default
+    include: ['src/**/*'],
+    exclude: ['src/**/*.test.ts', 'src/**/*.spec.ts'],
+    delay: 100,
+    ignoreInitial: false,
+    watchNewFiles: true,
+  },
 })

package.json

@@ -32,6 +32,7 @@
   },
   "dependencies": {
     "c12": "^3.0.4",
+    "chokidar": "^4.0.3",
     "consola": "^3.4.2",
     "defu": "^6.1.4",
     "exsolve": "^1.0.5",

pnpm-lock.yaml

@@ -14,21 +14,56 @@ import prettyBytes from 'pretty-bytes'
 import { rolldownBuild } from './builders/bundle'
 import { transformDir } from './builders/transform'
 import { analyzeDir, fmtPath } from './utils'
+import { startWatch } from './watch'
 
 /**
  * Build dist/ from src/
  */
 export async function build(config: BuildConfig): Promise<void> {
-  const start = Date.now()
+  // const start = Date.now()
 
   const pkgDir = normalizePath(config.cwd)
   const pkg = await readJSON(join(pkgDir, 'package.json')).catch(() => ({}))
   const ctx: BuildContext = { pkg, pkgDir }
 
+  // Check if watch mode is enabled
+  if (config.watch?.enabled) {
+    consola.log(
+      `👀 Starting watch mode for \`${ctx.pkg.name || '<no name>'}\` (\`${ctx.pkgDir}\`)`,
+    )
+
+    // Perform initial build
+    await performBuild(config, ctx)
+
+    // Start watching
+    const stopWatch = await startWatch(config, ctx, build)
+
+    // Handle graceful shutdown
+    const cleanup = () => {
+      consola.info('🛑 Stopping watch mode...')
+      stopWatch()
+      process.exit(0)
+    }
+
+    process.on('SIGINT', cleanup)
+    process.on('SIGTERM', cleanup)
+
+    // Keep the process alive
+    return new Promise(() => {}) // Never resolves, keeps watching
+  }
+
   consola.log(
     `📦 Building \`${ctx.pkg.name || '<no name>'}\` (\`${ctx.pkgDir}\`)`,
   )
 
+  await performBuild(config, ctx)
+}
+
+/**
+ * Perform the actual build process
+ */
+async function performBuild(config: BuildConfig, ctx: BuildContext): Promise<void> {
+  const start = Date.now()
   const hooks = config.hooks || {}
 
   await hooks.start?.(ctx)
@@ -55,10 +90,10 @@ export async function build(config: BuildConfig): Promise<void> {
       )
     }
     entry = { ...entry }
-    entry.outDir = normalizePath(entry.outDir || 'dist', pkgDir)
+    entry.outDir = normalizePath(entry.outDir || 'dist', ctx.pkgDir)
     entry.input = Array.isArray(entry.input)
-      ? entry.input.map(p => normalizePath(p, pkgDir))
-      : normalizePath(entry.input, pkgDir)
+      ? entry.input.map(p => normalizePath(p, ctx.pkgDir))
+      : normalizePath(entry.input, ctx.pkgDir)
     return entry
   })
 

src/build.ts

@@ -20,6 +20,10 @@ const args = parseArgs({
       type: 'boolean',
       default: false,
     },
+    watch: {
+      type: 'boolean',
+      default: false,
+    },
   },
 })
 
@@ -59,4 +63,5 @@ await build({
   cwd: args.values.dir,
   ...config,
   entries,
+  watch: args.values.watch ? { enabled: true, ...config.watch } : config.watch,
 })

src/cli.ts

@@ -111,8 +111,53 @@ export interface BuildHooks {
   ) => void | Promise<void>
 }
 
+export interface WatchOptions {
+  /**
+   * Enable watch mode.
+   *
+   * Defaults to `false` if not provided.
+   */
+  enabled?: boolean
+
+  /**
+   * Glob patterns for files to watch.
+   *
+   * Defaults to watching all source files if not provided.
+   */
+  include?: string[]
+
+  /**
+   * Glob patterns for files to ignore.
+   *
+   * Defaults to common ignore patterns if not provided.
+   */
+  exclude?: string[]
+
+  /**
+   * Delay in milliseconds before rebuilding after a file change.
+   *
+   * Defaults to `100` if not provided.
+   */
+  delay?: number
+
+  /**
+   * Whether to ignore the initial build when starting watch mode.
+   *
+   * Defaults to `false` if not provided.
+   */
+  ignoreInitial?: boolean
+
+  /**
+   * Whether to watch for new files being added.
+   *
+   * Defaults to `true` if not provided.
+   */
+  watchNewFiles?: boolean
+}
+
 export interface BuildConfig {
   cwd?: string | URL
   entries?: (BuildEntry | string)[]
   hooks?: BuildHooks
+  watch?: WatchOptions
 }