feat(build): support multi-entry output in shared package build script

scripts/build-shared-package.mjs

@@ -9,20 +9,25 @@ import { pathToFileURL } from "node:url";
 async function main() {
   const options = parseArgs(process.argv.slice(2));
   const packageDir = path.resolve(options.packageDir);
-  const entryPath = path.resolve(packageDir, options.entry);
   const outDir = path.resolve(packageDir, options.outDir);
 
   await fs.rm(outDir, { recursive: true, force: true });
   await fs.mkdir(outDir, { recursive: true });
 
   const bun = resolveBunRuntime();
+  const entries = options.entries.length > 0
+    ? options.entries
+    : [{ source: options.entry, name: "index" }];
+
+  for (const entry of entries) {
+    const entryPath = path.resolve(packageDir, entry.source);
     runBuild(bun, {
       entryPath,
       external: options.external,
       format: "esm",
-    outfile: path.join(outDir, "index.js"),
+      outfile: path.join(outDir, `${entry.name}.js`),
     });
-  const cjsOutfile = path.join(outDir, "index.cjs");
+    const cjsOutfile = path.join(outDir, `${entry.name}.cjs`);
     runBuild(bun, {
       entryPath,
       external: options.external,
@@ -30,6 +35,7 @@ async function main() {
       outfile: cjsOutfile,
     });
     await scrubCommonJsSourceFileUrls(cjsOutfile, packageDir);
+  }
 
   for (const asset of options.assets) {
     const source = path.resolve(packageDir, asset.source);
@@ -45,6 +51,7 @@ function parseArgs(argv) {
     outDir: "dist",
     external: [],
     assets: [],
+    entries: [],
   };
 
   for (let index = 0; index < argv.length; index += 1) {
@@ -57,6 +64,10 @@ function parseArgs(argv) {
       options.entry = readArgValue(argv, ++index, arg);
       continue;
     }
+    if (arg === "--entry-out") {
+      options.entries.push(parseEntryOutArg(readArgValue(argv, ++index, arg)));
+      continue;
+    }
     if (arg === "--out-dir") {
       options.outDir = readArgValue(argv, ++index, arg);
       continue;
@@ -79,6 +90,14 @@ function parseArgs(argv) {
   return options;
 }
 
+function parseEntryOutArg(value) {
+  const [source, name] = value.split(":");
+  if (!source || !name) {
+    throw new Error(`Invalid --entry-out value: ${value} (expected <source>:<name>)`);
+  }
+  return { source, name };
+}
+
 function readArgValue(argv, index, flag) {
   const value = argv[index];
   if (!value) {
@@ -155,6 +174,7 @@ function printUsage() {
 Options:
   --package-dir <dir>     Package root (default: current directory)
   --entry <file>          Entry file relative to package root (default: src/index.ts)
+  --entry-out <src:name>  Add an entry that emits <name>.js / <name>.cjs (repeatable)
   --out-dir <dir>         Output directory relative to package root (default: dist)
   --external <name>       Leave a module external (can be repeated)
   --asset <src[:dst]>     Copy an asset directory/file into out-dir (can be repeated)