From 423f20b11f910111f406879c5c3aa05886b339c7 Mon Sep 17 00:00:00 2001
From: uzlopak <aras.abbasi@googlemail.com>
Date: Fri, 3 Nov 2023 23:52:54 +0100
Subject: [PATCH] lib: set locale per cli

---
 doc/api/cli.md                   |  15 +++
 src/node.cc                      |   4 +
 src/node_i18n.cc                 |  17 +++
 src/node_i18n.h                  |   2 +
 src/node_options.cc              |   5 +
 src/node_options.h               |   1 +
 test/parallel/test-icu-locale.js | 179 +++++++++++++++++++++++++++++++
 7 files changed, 223 insertions(+)
 create mode 100644 test/parallel/test-icu-locale.js

diff --git a/doc/api/cli.md b/doc/api/cli.md
index 5f29c497426db6..7503c3dea1b98f 100644
--- a/doc/api/cli.md
+++ b/doc/api/cli.md
@@ -1138,6 +1138,19 @@ surface on other platforms, but the performance impact may be severe.
 This flag is inherited from V8 and is subject to change upstream. It may
 disappear in a non-semver-major release.
 
+### `--locale`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+Set the default locale used by ICU (`Intl` object). It expects a string
+representing the language version as defined in [RFC 5646][] (also known as
+BCP 47). (Overrides `LOCALE`.)
+
+Examples of valid language codes include "en", "en-US", "fr", "fr-FR", "es-ES",
+etc.
+
 ### `--max-http-header-size=size`
 
 <!-- YAML
@@ -2344,6 +2357,7 @@ Node.js options that are allowed are:
 * `--inspect-port`, `--debug-port`
 * `--inspect-publish-uid`
 * `--inspect`
+* `--locale`
 * `--max-http-header-size`
 * `--napi-modules`
 * `--no-addons`
@@ -2769,6 +2783,7 @@ done
 [OSSL_PROVIDER-legacy]: https://www.openssl.org/docs/man3.0/man7/OSSL_PROVIDER-legacy.html
 [Permission Model]: permissions.md#permission-model
 [REPL]: repl.md
+[RFC 5646]: https://www.rfc-editor.org/rfc/rfc5646.txt
 [ScriptCoverage]: https://chromedevtools.github.io/devtools-protocol/tot/Profiler#type-ScriptCoverage
 [ShadowRealm]: https://github.com/tc39/proposal-shadowrealm
 [Source Map]: https://sourcemaps.info/spec.html
diff --git a/src/node.cc b/src/node.cc
index a9336a14304fc6..fdcbd1f15c5bb8 100644
--- a/src/node.cc
+++ b/src/node.cc
@@ -949,6 +949,10 @@ static ExitCode InitializeNodeWithArgsInternal(
   }
 # endif
 
+  if (!per_process::cli_options->locale.empty()) {
+    i18n::SetDefaultLocale(per_process::cli_options->locale.c_str());
+  }
+
 #endif  // defined(NODE_HAVE_I18N_SUPPORT)
 
   // We should set node_is_initialized here instead of in node::Start,
diff --git a/src/node_i18n.cc b/src/node_i18n.cc
index d45325954d9807..2bd9576350fa05 100644
--- a/src/node_i18n.cc
+++ b/src/node_i18n.cc
@@ -61,6 +61,7 @@
 #include <unicode/ucnv.h>
 #include <unicode/udata.h>
 #include <unicode/uidna.h>
+#include <unicode/uloc.h>
 #include <unicode/ulocdata.h>
 #include <unicode/urename.h>
 #include <unicode/ustring.h>
@@ -601,6 +602,22 @@ void SetDefaultTimeZone(const char* tzid) {
   CHECK(U_SUCCESS(status));
 }
 
+void SetDefaultLocale(const char* localeid) {
+  UErrorCode status = U_ZERO_ERROR;
+
+  if (localeid != nullptr) {
+    size_t localelen = strlen(localeid) + 1;
+    MaybeStackBuffer<UChar, 256> id(localelen);
+    u_charsToUChars(localeid, id.out(), localelen);
+    // This is threadsafe:
+    uloc_setDefault(localeid, &status);
+    CHECK(U_SUCCESS(status));
+  } else {
+    uloc_setDefault(localeid, &status);
+    CHECK(U_SUCCESS(status));
+  }
+}
+
 int32_t ToUnicode(MaybeStackBuffer<char>* buf,
                   const char* input,
                   size_t length) {
diff --git a/src/node_i18n.h b/src/node_i18n.h
index e516282865fb18..887353e6c3bad3 100644
--- a/src/node_i18n.h
+++ b/src/node_i18n.h
@@ -42,6 +42,8 @@ bool InitializeICUDirectory(const std::string& path, std::string* error);
 
 void SetDefaultTimeZone(const char* tzid);
 
+void SetDefaultLocale(const char* localid);
+
 enum class idna_mode {
   // Default mode for maximum compatibility.
   kDefault,
diff --git a/src/node_options.cc b/src/node_options.cc
index 29cb7fc6b29b89..1530e08fb974a5 100644
--- a/src/node_options.cc
+++ b/src/node_options.cc
@@ -934,6 +934,11 @@ PerProcessOptionsParser::PerProcessOptionsParser(
             ,
             &PerProcessOptions::icu_data_dir,
             kAllowedInEnvvar);
+
+  AddOption("--locale",
+            "Set the locale of the node instance",
+            &PerProcessOptions::locale,
+            kAllowedInEnvvar);
 #endif
 
 #if HAVE_OPENSSL
diff --git a/src/node_options.h b/src/node_options.h
index 30955c779714ce..2c08ec45f25855 100644
--- a/src/node_options.h
+++ b/src/node_options.h
@@ -271,6 +271,7 @@ class PerProcessOptions : public Options {
 
 #ifdef NODE_HAVE_I18N_SUPPORT
   std::string icu_data_dir;
+  std::string locale;
 #endif
 
   // Per-process because they affect singleton OpenSSL shared library state,
diff --git a/test/parallel/test-icu-locale.js b/test/parallel/test-icu-locale.js
new file mode 100644
index 00000000000000..32b15c26645b76
--- /dev/null
+++ b/test/parallel/test-icu-locale.js
@@ -0,0 +1,179 @@
+'use strict';
+const common = require('../common');
+const { spawnSyncAndExitWithoutError } = require('../common/child_process');
+
+if (!common.hasIntl)
+  common.skip('Intl not present.');
+
+if (!common.isMainThread)
+  common.skip('process.env.LOCALE is not intercepted in Workers');
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=fr-FR',
+    '-p',
+    'Intl?.Collator().resolvedOptions().locale',
+  ],
+  {
+    signal: null,
+    stdout: /fr-FR/,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=de-DE',
+    '-p',
+    'Intl?.Collator().resolvedOptions().locale',
+  ],
+  {
+    signal: null,
+    stdout: /de-DE/,
+  });
+
+// NumberFormat
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  ['--locale=de-DE', '-p', '(123456.789).toLocaleString(undefined, { style: "currency", currency: "EUR" })'],
+  {
+    signal: null,
+    stdout: /123\.456,79\xa0€/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=jp-JP',
+    '-p',
+    '(123456.789).toLocaleString(undefined, { style: "currency", currency: "JPY" })',
+  ],
+  {
+    signal: null,
+    stdout: /JP¥\xa0123,457/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=en-IN',
+    '-p',
+    '(123456.789).toLocaleString(undefined, { maximumSignificantDigits: 3  })',
+  ],
+  {
+    signal: null,
+    stdout: /1,23,000/u,
+  });
+
+// DateTimeFormat
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=en-GB',
+    '-p',
+    'new Date(Date.UTC(2012, 11, 20, 3, 0, 0)).toLocaleString(undefined,  { timeZone: "UTC" })',
+  ],
+  {
+    signal: null,
+    stdout: /20\/12\/2012, 03:00:00/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=ko-KR',
+    '-p',
+    'new Date(Date.UTC(2012, 11, 20, 3, 0, 0)).toLocaleString(undefined,  { timeZone: "UTC" })',
+  ],
+  {
+    signal: null,
+    stdout: /2012\. 12\. 20\. 오전 3:00:00/u,
+  });
+
+// ListFormat
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=en-US',
+    '-p',
+    'new Intl.ListFormat(undefined, {style: "long", type:"conjunction"}).format(["a", "b", "c"])',
+  ],
+  {
+    signal: null,
+    stdout: /a, b, and c/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=de-DE',
+    '-p',
+    'new Intl.ListFormat(undefined, {style: "long", type:"conjunction"}).format(["a", "b", "c"])',
+  ],
+  {
+    signal: null,
+    stdout: /a, b und c/u,
+  });
+
+// RelativeTimeFormat
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=en',
+    '-p',
+    'new Intl.RelativeTimeFormat(undefined, { numeric: "auto" }).format(3, "quarter")',
+  ],
+  {
+    signal: null,
+    stdout: /in 3 quarters/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=es',
+    '-p',
+    'new Intl.RelativeTimeFormat(undefined, { numeric: "auto" }).format(2, "day")',
+  ],
+  {
+    signal: null,
+    stdout: /pasado mañana/u,
+  });
+
+// Collator
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=de',
+    '-p',
+    '["Z", "a", "z", "ä"].sort(new Intl.Collator().compare).join(",")',
+  ],
+  {
+    signal: null,
+    stdout: /a,ä,z,Z/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=sv',
+    '-p',
+    '["Z", "a", "z", "ä"].sort(new Intl.Collator().compare).join(",")',
+  ],
+  {
+    signal: null,
+    stdout: /a,z,Z,ä/u,
+  });
+
+spawnSyncAndExitWithoutError(
+  process.execPath,
+  [
+    '--locale=de',
+    '-p',
+    '["Z", "a", "z", "ä"].sort(new Intl.Collator(undefined, { caseFirst: "upper" }).compare).join(",")',
+  ],
+  {
+    signal: null,
+    stdout: /a,ä,Z,z/u,
+  });