From 88875e6146e290f1e7f67cbd66f7cecae46883be Mon Sep 17 00:00:00 2001
From: EGOIST <0x142857@gmail.com>
Date: Tue, 23 Nov 2021 23:04:58 +0800
Subject: [PATCH] feat(watch): only trigger rebuild when the changed file is
 actually imported

---
 README.md            |  3 +--
 src/esbuild/index.ts | 32 ++++++++++++++++++++++----------
 src/index.ts         |  6 ++++++
 3 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/README.md b/README.md
index bc1f636c..1f03b36e 100644
--- a/README.md
+++ b/README.md
@@ -38,7 +38,6 @@ tsup src/index.ts src/cli.ts
 
 This will output `dist/index.js` and `dist/cli.js`.
 
-
 ## Documentation
 
 For complete usages, please dive into the [docs](https://tsup.egoist.sh).
@@ -49,7 +48,7 @@ For complete usages, please dive into the [docs](https://tsup.egoist.sh).
 
 ## Project Stats
 
-![Alt](https://repobeats.axiom.co/api/embed/4ef361ec8445b33c2dab451e1d23784015834c72.svg "Repobeats analytics image")
+![Alt](https://repobeats.axiom.co/api/embed/4ef361ec8445b33c2dab451e1d23784015834c72.svg 'Repobeats analytics image')
 
 ## License
 
diff --git a/src/esbuild/index.ts b/src/esbuild/index.ts
index 310e527f..962b3f3e 100644
--- a/src/esbuild/index.ts
+++ b/src/esbuild/index.ts
@@ -38,7 +38,13 @@ export async function runEsbuild(
     format,
     css,
     logger,
-  }: { format: Format; css?: Map<string, string>; logger: Logger }
+    buildDependencies,
+  }: {
+    format: Format
+    css?: Map<string, string>
+    buildDependencies: Set<string>
+    logger: Logger
+  }
 ) {
   const pkg = await loadPkg(process.cwd())
   const deps = await getDeps(process.cwd())
@@ -174,7 +180,7 @@ export async function runEsbuild(
       keepNames: options.keepNames,
       incremental: !!options.watch,
       pure: typeof options.pure === 'string' ? [options.pure] : options.pure,
-      metafile: Boolean(options.metafile),
+      metafile: true,
     })
   } catch (error) {
     logger.error(format, 'Build failed')
@@ -270,13 +276,19 @@ export async function runEsbuild(
     )
   }
 
-  if (options.metafile && result?.metafile) {
-    const outPath = path.resolve(outDir, `metafile-${format}.json`)
-    await fs.promises.mkdir(path.dirname(outPath), { recursive: true })
-    await fs.promises.writeFile(
-      outPath,
-      JSON.stringify(result.metafile),
-      'utf8'
-    )
+  if (result.metafile) {
+    for (const file of Object.keys(result.metafile.inputs)) {
+      buildDependencies.add(file)
+    }
+
+    if (options.metafile) {
+      const outPath = path.resolve(outDir, `metafile-${format}.json`)
+      await fs.promises.mkdir(path.dirname(outPath), { recursive: true })
+      await fs.promises.writeFile(
+        outPath,
+        JSON.stringify(result.metafile),
+        'utf8'
+      )
+    }
   }
 }
diff --git a/src/index.ts b/src/index.ts
index af68344e..7733a944 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -138,6 +138,8 @@ export async function build(_options: Options) {
 
         if (!options.dts?.only) {
           let existingOnSuccess: ChildProcess | undefined
+          /** Files imported by the entry */
+          const buildDependencies: Set<string> = new Set()
 
           async function killPreviousProcess() {
             if (existingOnSuccess) {
@@ -158,6 +160,7 @@ export async function build(_options: Options) {
 
           const buildAll = async () => {
             const killPromise = killPreviousProcess()
+            buildDependencies.clear()
 
             if (options.clean) {
               const extraPatterns = Array.isArray(options.clean)
@@ -177,6 +180,7 @@ export async function build(_options: Options) {
                   format,
                   css: index === 0 ? css : undefined,
                   logger,
+                  buildDependencies,
                 })
               ),
             ])
@@ -238,6 +242,8 @@ export async function build(_options: Options) {
               ignored,
             })
             watcher.on('all', async (type, file) => {
+              if (!buildDependencies.has(file)) return
+
               logger.info('CLI', `Change detected: ${type} ${file}`)
               debouncedBuildAll()
             })