feat(compiler-sfc): support syntax export { default } from '...'

packages/compiler-sfc/src/rewriteDefault.ts

@@ -2,7 +2,7 @@ import { parse, ParserPlugin } from '@babel/parser'
 import MagicString from 'magic-string'
 
 const defaultExportRE = /((?:^|\n|;)\s*)export(\s*)default/
-const namedDefaultExportRE = /((?:^|\n|;)\s*)export(.+)as(\s*)default/s
+const namedDefaultExportRE = /((?:^|\n|;)\s*)export(.+)(?:as)?(\s*)default/s
 const exportDefaultClassRE =
   /((?:^|\n|;)\s*)export\s+default\s+class\s+([\w$]+)/
 
@@ -45,21 +45,39 @@ export function rewriteDefault(
       s.overwrite(node.start!, node.declaration.start!, `const ${as} = `)
     }
     if (node.type === 'ExportNamedDeclaration') {
-      node.specifiers.forEach(specifier => {
+      for (const specifier of node.specifiers) {
         if (
           specifier.type === 'ExportSpecifier' &&
           specifier.exported.type === 'Identifier' &&
           specifier.exported.name === 'default'
         ) {
-          const end = specifier.end!
-          s.overwrite(
-            specifier.start!,
-            input.charAt(end) === ',' ? end + 1 : end,
-            ``
-          )
+          if (node.source) {
+            if (specifier.local.name === 'default') {
+              const end = specifierEnd(input, specifier.local.end!, node.end)
+              s.prepend(
+                `import { default as __VUE_DEFAULT__ } from '${node.source.value}'\n`
+              )
+              s.overwrite(specifier.start!, end, ``)
+              s.append(`\nconst ${as} = __VUE_DEFAULT__`)
+              continue
+            } else {
+              const end = specifierEnd(input, specifier.exported.end!, node.end)
+              s.prepend(
+                `import { ${input.slice(
+                  specifier.local.start!,
+                  specifier.local.end!
+                )} } from '${node.source?.value}'\n`
+              )
+              s.overwrite(specifier.start!, end, ``)
+              s.append(`\nconst ${as} = ${specifier.local.name}`)
+              continue
+            }
+          }
+          const end = specifierEnd(input, specifier.end!, node.end)
+          s.overwrite(specifier.start!, end, ``)
           s.append(`\nconst ${as} = ${specifier.local.name}`)
         }
-      })
+      }
     }
   })
   return s.toString()
@@ -68,3 +86,21 @@ export function rewriteDefault(
 export function hasDefaultExport(input: string): boolean {
   return defaultExportRE.test(input) || namedDefaultExportRE.test(input)
 }
+
+function specifierEnd(input: string, end: number, nodeEnd: number | null) {
+  // export { default   , foo } ...
+  let hasCommas = false
+  let oldEnd = end
+  while (end < nodeEnd!) {
+    if (/\s/.test(input.charAt(end))) {
+      end++
+    } else if (input.charAt(end) === ',') {
+      end++
+      hasCommas = true
+      break
+    } else if (input.charAt(end) === '}') {
+      break
+    }
+  }
+  return hasCommas ? end : oldEnd
+}