From f5ec42e4b0c7d94dfc59c9b93ff603b61efb2b11 Mon Sep 17 00:00:00 2001
From: ygj6 <yuangongji@foxmail.com>
Date: Sat, 1 May 2021 22:15:35 +0800
Subject: [PATCH] fix(dev): strip utf-8 bom (#3162) (#3171)

---
 packages/playground/resolve/__tests__/resolve.spec.ts | 4 ++++
 packages/playground/resolve/index.html                | 7 +++++++
 packages/playground/resolve/utf8-bom/main.js          | 3 +++
 packages/vite/src/node/plugins/importAnalysis.ts      | 4 ++++
 4 files changed, 18 insertions(+)
 create mode 100644 packages/playground/resolve/utf8-bom/main.js

diff --git a/packages/playground/resolve/__tests__/resolve.spec.ts b/packages/playground/resolve/__tests__/resolve.spec.ts
index 0bb7c238e77893..0b0f1c7fdc8896 100644
--- a/packages/playground/resolve/__tests__/resolve.spec.ts
+++ b/packages/playground/resolve/__tests__/resolve.spec.ts
@@ -1,5 +1,9 @@
 import { isBuild } from '../../testUtils'
 
+test('bom import', async () => {
+  expect(await page.textContent('.utf8-bom')).toMatch('[success]')
+})
+
 test('deep import', async () => {
   expect(await page.textContent('.deep-import')).toMatch('[2,4]')
 })
diff --git a/packages/playground/resolve/index.html b/packages/playground/resolve/index.html
index 722d66de5340ff..aada0bd1bdd972 100644
--- a/packages/playground/resolve/index.html
+++ b/packages/playground/resolve/index.html
@@ -1,5 +1,8 @@
 <h1>Resolve</h1>
 
+<h2>Utf8-bom import</h2>
+<p class="utf8-bom">fail</p>
+
 <h2>Deep import</h2>
 <p>Should show [2,4]:<span class="pre deep-import">fail</span></p>
 
@@ -62,6 +65,10 @@ <h2>resolve.conditions</h2>
     document.querySelector(selector).textContent = text
   }
 
+  // import from a utf-8 bom file
+  import { msg as bomMsg } from './utf8-bom/main.js'
+  text('.utf8-bom', bomMsg)
+
   // deep import
   import slicedToArray from '@babel/runtime/helpers/esm/slicedToArray'
 
diff --git a/packages/playground/resolve/utf8-bom/main.js b/packages/playground/resolve/utf8-bom/main.js
new file mode 100644
index 00000000000000..6273e5ac04e016
--- /dev/null
+++ b/packages/playground/resolve/utf8-bom/main.js
@@ -0,0 +1,3 @@
+import '@babel/runtime/helpers/esm/slicedToArray'
+
+export const msg = '[success]'
diff --git a/packages/vite/src/node/plugins/importAnalysis.ts b/packages/vite/src/node/plugins/importAnalysis.ts
index 040558b9f79645..cf83bdb6419e2d 100644
--- a/packages/vite/src/node/plugins/importAnalysis.ts
+++ b/packages/vite/src/node/plugins/importAnalysis.ts
@@ -112,6 +112,10 @@ export function importAnalysisPlugin(config: ResolvedConfig): Plugin {
       const rewriteStart = Date.now()
       await init
       let imports: readonly ImportSpecifier[] = []
+      // strip UTF-8 BOM
+      if (source.charCodeAt(0) === 0xfeff) {
+        source = source.slice(1)
+      }
       try {
         imports = parseImports(source)[0]
       } catch (e) {