build: adjust esm formats

scripts/build.js

@@ -27,7 +27,8 @@ const targets = args._
 const formats = args.formats || args.f
 const devOnly = args.devOnly || args.d
 const prodOnly = !devOnly && (args.prodOnly || args.p)
-const buildTypes = args.t || args.types
+const isRelease = args.release
+const buildTypes = args.t || args.types || isRelease
 const buildAllMatching = args.all || args.a
 const lean = args.lean || args.l
 const commit = execa.sync('git', ['rev-parse', 'HEAD']).stdout.slice(0, 7)
@@ -54,6 +55,11 @@ async function build(target) {
   const pkgDir = path.resolve(`packages/${target}`)
   const pkg = require(`${pkgDir}/package.json`)
 
+  // only build published packages for release
+  if (isRelease && pkg.private) {
+    return
+  }
+
   // if building a specific format, do not remove dist.
   if (!formats) {
     await fs.remove(`${pkgDir}/dist`)