rename packages, refactor out tailwind compiler,

go/webbundler/export_shim.go

@@ -0,0 +1,89 @@
+package webbundler
+
+// defaultExportShimPlugin bridges two ESM-strictness mismatches that
+// existed in the previous custom bundler:
+//
+//  1. `export default function Name` also emits `export { Name }` so
+//     callers using `import { Name } from "..."` resolve correctly.
+//  2. If the source declares `export function/class/const Name` (or
+//     `Name`) where Name matches the file's basename, synthesize
+//     `export { Name as default }` so callers using `import Name from
+//     "..."` resolve correctly.  The old bundler made every IIFE
+//     return value available as both the named symbol AND the default
+//     import; standard ESM does not, so esbuild needs the shim until
+//     callers migrate to named imports throughout.
+
+import (
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+
+	esbuild "github.com/evanw/esbuild/pkg/api"
+)
+
+func defaultExportShimPlugin() esbuild.Plugin {
+	return esbuild.Plugin{
+		Name: "default-export-shim",
+		Setup: func(b esbuild.PluginBuild) {
+			b.OnLoad(esbuild.OnLoadOptions{Filter: `\.(js|ts)$`}, func(args esbuild.OnLoadArgs) (esbuild.OnLoadResult, error) {
+				raw, err := os.ReadFile(args.Path)
+				if err != nil {
+					return esbuild.OnLoadResult{}, err
+				}
+				out := addNamedExportForDefault(string(raw))
+				out = addDefaultExportForFilenameMatch(out, args.Path)
+				loader := esbuild.LoaderJS
+				if strings.HasSuffix(args.Path, ".ts") {
+					loader = esbuild.LoaderTS
+				}
+				return esbuild.OnLoadResult{Contents: &out, Loader: loader}, nil
+			})
+		},
+	}
+}
+
+var reFilenameMatchExport = regexp.MustCompile(`(?m)^export\s+(?:async\s+)?(?:function|class|const|let|var)\s+(\w+)`)
+var reExistingDefault = regexp.MustCompile(`(?m)^export\s+default\b`)
+
+// addDefaultExportForFilenameMatch synthesizes `export { Name as
+// default }` if the source declares a top-level export whose name
+// matches the file's basename and the file does not already have a
+// default export.  This preserves the old bundler's behavior where
+// `import Foo from "./Foo.js"` resolved against `export function
+// Foo(...)`.
+func addDefaultExportForFilenameMatch(src, path string) string {
+	if reExistingDefault.MatchString(src) {
+		return src
+	}
+	base := filepath.Base(path)
+	base = strings.TrimSuffix(base, filepath.Ext(base))
+	if base == "" {
+		return src
+	}
+	for _, m := range reFilenameMatchExport.FindAllStringSubmatch(src, -1) {
+		if m[1] == base {
+			return src + "\nexport { " + base + " as default };\n"
+		}
+	}
+	return src
+}
+
+var reExportDefaultDecl = regexp.MustCompile(`(?m)^export\s+default\s+(?:async\s+)?(?:function|class)\s+(\w+)`)
+
+func addNamedExportForDefault(src string) string {
+	matches := reExportDefaultDecl.FindAllStringSubmatch(src, -1)
+	if len(matches) == 0 {
+		return src
+	}
+	names := make([]string, 0, len(matches))
+	seen := map[string]bool{}
+	for _, m := range matches {
+		if seen[m[1]] {
+			continue
+		}
+		seen[m[1]] = true
+		names = append(names, m[1])
+	}
+	return src + "\nexport { " + strings.Join(names, ", ") + " };\n"
+}