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Commit 6657202

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guybedfordguybedford
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esm: Implement "exports" proposal
1 parent 9868126 commit 6657202

7 files changed

Lines changed: 122 additions & 9 deletions

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‎src/env.h‎

Lines changed: 5 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -92,13 +92,18 @@ struct PackageConfig {
9292
enum class Exists { Yes, No };
9393
enum class IsValid { Yes, No };
9494
enum class HasMain { Yes, No };
95+
enum class HasExports { Yes, No };
9596
enum PackageType : uint32_t { None = 0, CommonJS, Module };
9697

9798
const Exists exists;
9899
const IsValid is_valid;
99100
const HasMain has_main;
100101
const std::string main;
101102
const PackageType type;
103+
104+
const HasExports has_exports;
105+
const v8::CopyablePersistentTraits<v8::Value>::CopyablePersistent exports;
106+
102107
};
103108
} // namespace loader
104109

‎src/module_wrap.cc‎

Lines changed: 93 additions & 9 deletions
Original file line numberDiff line numberDiff line change
@@ -39,6 +39,7 @@ using v8::Module;
3939
using v8::Nothing;
4040
using v8::Number;
4141
using v8::Object;
42+
using v8::Persistent;
4243
using v8::PrimitiveArray;
4344
using v8::Promise;
4445
using v8::ScriptCompiler;
@@ -537,6 +538,7 @@ using Exists = PackageConfig::Exists;
537538
using IsValid = PackageConfig::IsValid;
538539
using HasMain = PackageConfig::HasMain;
539540
using PackageType = PackageConfig::PackageType;
541+
using HasExports = PackageConfig::HasExports;
540542

541543
Maybe<const PackageConfig*> GetPackageConfig(Environment* env,
542544
const std::string& path,
@@ -558,7 +560,8 @@ Maybe<const PackageConfig*> GetPackageConfig(Environment* env,
558560
if (source.IsNothing()) {
559561
auto entry = env->package_json_cache.emplace(path,
560562
PackageConfig { Exists::No, IsValid::Yes, HasMain::No, "",
561-
PackageType::None });
563+
PackageType::None, HasExports::No,
564+
Persistent<Value>() });
562565
return Just(&entry.first->second);
563566
}
564567

@@ -578,7 +581,8 @@ Maybe<const PackageConfig*> GetPackageConfig(Environment* env,
578581
!pkg_json_v->ToObject(context).ToLocal(&pkg_json)) {
579582
env->package_json_cache.emplace(path,
580583
PackageConfig { Exists::Yes, IsValid::No, HasMain::No, "",
581-
PackageType::None });
584+
PackageType::None, HasExports::No,
585+
Persistent<Value>() });
582586
std::string msg = "Invalid JSON in '" + path +
583587
"' imported from " + base.ToFilePath();
584588
node::THROW_ERR_INVALID_PACKAGE_CONFIG(env, msg.c_str());
@@ -609,22 +613,23 @@ Maybe<const PackageConfig*> GetPackageConfig(Environment* env,
609613
}
610614

611615
Local<Value> exports_v;
616+
Persistent<Value> exports;
612617
if (pkg_json->Get(env->context(),
613618
env->exports_string()).ToLocal(&exports_v) &&
614-
(exports_v->IsObject() || exports_v->IsString() ||
615-
exports_v->IsBoolean())) {
616-
Global<Value> exports;
619+
(exports_v->IsObject() ||
620+
(exports_v->IsBoolean() && exports_v->IsFalse()))) {
617621
exports.Reset(env->isolate(), exports_v);
618622

619623
auto entry = env->package_json_cache.emplace(path,
620624
PackageConfig { Exists::Yes, IsValid::Yes, has_main, main_std,
621-
pkg_type });
625+
pkg_type, HasExports::Yes, exports });
622626
return Just(&entry.first->second);
623627
}
624628

625629
auto entry = env->package_json_cache.emplace(path,
626630
PackageConfig { Exists::Yes, IsValid::Yes, has_main, main_std,
627-
pkg_type });
631+
pkg_type, HasExports::No,
632+
Persistent<Value>() });
628633
return Just(&entry.first->second);
629634
}
630635

@@ -646,7 +651,7 @@ Maybe<const PackageConfig*> GetPackageScopeConfig(Environment* env,
646651
if (pjson_url.path() == last_pjson_url.path()) {
647652
auto entry = env->package_json_cache.emplace(pjson_url.ToFilePath(),
648653
PackageConfig { Exists::No, IsValid::Yes, HasMain::No, "",
649-
PackageType::None });
654+
PackageType::None, HasExports::No, Persistent<Value>() });
650655
const PackageConfig* pcfg = &entry.first->second;
651656
return Just(pcfg);
652657
}
@@ -772,6 +777,20 @@ Maybe<URL> PackageMainResolve(Environment* env,
772777
const PackageConfig& pcfg,
773778
const URL& base) {
774779
if (pcfg.exists == Exists::Yes) {
780+
Local<Value> exports = pcfg.exports.Get(env->isolate());
781+
if (pcfg.has_exports == HasExports::Yes && exports->IsObject()) {
782+
Local<Object> exports_obj = exports.As<Object>();
783+
Local<String> dot_string = String::NewFromUtf8(env->isolate(), ".",
784+
v8::NewStringType::kNormal).ToLocalChecked();
785+
auto dot_main =
786+
exports_obj->Get(env->context(), dot_string).ToLocalChecked();
787+
if (dot_main->IsString()) {
788+
Utf8Value main_utf8(env->isolate(), dot_main.As<v8::String>());
789+
std::string main(*main_utf8, main_utf8.length());
790+
URL main_url("./" + main, pjson_url);
791+
return FinalizeResolution(env, main_url, base);
792+
}
793+
}
775794
if (pcfg.has_main == HasMain::Yes) {
776795
URL resolved(pcfg.main, pjson_url);
777796
const std::string& path = resolved.ToFilePath();
@@ -800,6 +819,66 @@ Maybe<URL> PackageMainResolve(Environment* env,
800819
return Nothing<URL>();
801820
}
802821

822+
Maybe<URL> PackageExportsResolve(Environment* env,
823+
const URL& pjson_url,
824+
const std::string& pkg_subpath,
825+
const PackageConfig& pcfg,
826+
const URL& base) {
827+
Isolate* isolate = env->isolate();
828+
Local<Context> context = env->context();
829+
Local<Value> exports = pcfg.exports.Get(isolate);
830+
if (exports->IsObject()) {
831+
Local<Object> exports_obj = exports.As<Object>();
832+
Local<String> subpath = String::NewFromUtf8(isolate,
833+
pkg_subpath.c_str(), v8::NewStringType::kNormal).ToLocalChecked();
834+
835+
auto target = exports_obj->Get(context, subpath).ToLocalChecked();
836+
// TODO(@guybedford): Target validation
837+
if (target->IsString()) {
838+
Utf8Value target_utf8(isolate, target.As<v8::String>());
839+
std::string target(*target_utf8, target_utf8.length());
840+
if (target.substr(0, 2) == "./") {
841+
URL target_url(target, pjson_url);
842+
return FinalizeResolution(env, target_url, base);
843+
}
844+
}
845+
846+
Local<String> best_match;
847+
std::string best_match_str = "";
848+
Local<Array> keys =
849+
exports_obj->GetOwnPropertyNames(context).ToLocalChecked();
850+
for (uint32_t i = 0; i < keys->Length(); ++i) {
851+
Local<String> key = keys->Get(context, i).ToLocalChecked().As<String>();
852+
Utf8Value key_utf8(isolate, key);
853+
std::string key_str(*key_utf8, key_utf8.length());
854+
if (key_str.back() != '/') continue;
855+
if (pkg_subpath.substr(0, key_str.length()) == key_str &&
856+
key_str.length() > best_match_str.length()) {
857+
best_match = key;
858+
best_match_str = key_str;
859+
}
860+
}
861+
862+
if (best_match_str.length() > 0) {
863+
auto target = exports_obj->Get(context, best_match).ToLocalChecked();
864+
if (target->IsString()) {
865+
Utf8Value target_utf8(isolate, target.As<v8::String>());
866+
std::string target(*target_utf8, target_utf8.length());
867+
if (target.back() == '/' && target.substr(0, 2) == "./") {
868+
std::string subpath = pkg_subpath.substr(best_match_str.length());
869+
URL target_url(target + subpath, pjson_url);
870+
return FinalizeResolution(env, target_url, base);
871+
}
872+
}
873+
}
874+
}
875+
std::string msg = "Package exports for '" +
876+
URL(".", pjson_url).ToFilePath() + "' do not define a '" + pkg_subpath +
877+
"' subpath, imported from " + base.ToFilePath();
878+
node::THROW_ERR_MODULE_NOT_FOUND(env, msg.c_str());
879+
return Nothing<URL>();
880+
}
881+
803882
Maybe<URL> PackageResolve(Environment* env,
804883
const std::string& specifier,
805884
const URL& base) {
@@ -847,7 +926,12 @@ Maybe<URL> PackageResolve(Environment* env,
847926
if (!pkg_subpath.length()) {
848927
return PackageMainResolve(env, pjson_url, *pcfg.FromJust(), base);
849928
} else {
850-
return FinalizeResolution(env, URL(pkg_subpath, pjson_url), base);
929+
if (pcfg.FromJust()->has_exports == HasExports::Yes) {
930+
return PackageExportsResolve(env, pjson_url, pkg_subpath,
931+
*pcfg.FromJust(), base);
932+
} else {
933+
return FinalizeResolution(env, URL(pkg_subpath, pjson_url), base);
934+
}
851935
}
852936
CHECK(false);
853937
// Cross-platform root check.

‎test/es-module/test-esm-exports.mjs‎

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,14 @@
1+
// Flags: --experimental-modules
2+
3+
import { mustCall } from '../common/index.mjs';
4+
import { ok, strictEqual } from 'assert';
5+
6+
import { asdf } from '../fixtures/pkgexports.mjs';
7+
import { loadMissing } from '../fixtures/pkgexports-missing.mjs';
8+
9+
strictEqual(asdf, 'asdf');
10+
11+
loadMissing().catch(mustCall((err) => {
12+
ok(err.message.toString().startsWith('Package exports'));
13+
ok(err.message.toString().indexOf('do not define a \'./missing\' subpath'));
14+
}));

‎test/fixtures/node_modules/pkgexports/asdf.js‎

Lines changed: 1 addition & 0 deletions
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‎test/fixtures/node_modules/pkgexports/package.json‎

Lines changed: 5 additions & 0 deletions
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‎test/fixtures/pkgexports-missing.mjs‎

Lines changed: 3 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,3 @@
1+
export function loadMissing () {
2+
return import('pkgexports/missing');
3+
}

‎test/fixtures/pkgexports.mjs‎

Lines changed: 1 addition & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1 @@
1+
export { default as asdf } from 'pkgexports/asdf';

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