esm: Treat all non-nullish values the same

doc/api/esm.md

@@ -268,6 +268,8 @@ import feature from 'es-module-package/features/x.js';
 If a package has no exports, setting `"exports": false` can be used instead of
 `"exports": {}` to indicate the package does not intent for submodules to be
 exposed.
+This is just a convention that works because `false`, just like `{}`, has no
+iterable own properties.
 
 ## <code>import</code> Specifiers
 

src/module_wrap.cc

@@ -615,8 +615,7 @@ Maybe<const PackageConfig*> GetPackageConfig(Environment* env,
   Persistent<Value> exports;
   if (pkg_json->Get(env->context(),
       env->exports_string()).ToLocal(&exports_v) &&
-      (exports_v->IsObject() ||
-      (exports_v->IsBoolean() && exports_v->IsFalse()))) {
+      !exports_v->IsNullOrUndefined()) {
     exports.Reset(env->isolate(), exports_v);
 
     auto entry = env->package_json_cache.emplace(path,

test/es-module/test-esm-exports.mjs

@@ -4,7 +4,7 @@ import { mustCall } from '../common/index.mjs';
 import { ok, strictEqual } from 'assert';
 
 import { asdf, asdf2 } from '../fixtures/pkgexports.mjs';
-import { loadMissing } from '../fixtures/pkgexports-missing.mjs';
+import { loadMissing, loadFromNumber } from '../fixtures/pkgexports-missing.mjs';
 
 strictEqual(asdf, 'asdf');
 strictEqual(asdf2, 'asdf');
@@ -13,3 +13,8 @@ loadMissing().catch(mustCall((err) => {
   ok(err.message.toString().startsWith('Package exports'));
   ok(err.message.toString().indexOf('do not define a \'./missing\' subpath'));
 }));
+
+loadFromNumber().catch(mustCall((err) => {
+  ok(err.message.toString().startsWith('Package exports'));
+  ok(err.message.toString().indexOf('do not define a \'./missing\' subpath'));
+}));

test/fixtures/pkgexports-missing.mjs

@@ -1,3 +1,7 @@
-export function loadMissing () {
+export function loadMissing() {
   return import('pkgexports/missing');
 }
+
+export function loadFromNumber() {
+  return import('pkgexports-number/hidden.js');
+}