nodejs · guybedford · Feb 26, 2020
diff --git a/lib/internal/process/esm_loader.js b/lib/internal/process/esm_loader.js
@@ -3,7 +3,6 @@
 const {
   ERR_VM_DYNAMIC_IMPORT_CALLBACK_MISSING,
 } = require('internal/errors').codes;
-const assert = require('internal/assert');
 const { Loader } = require('internal/modules/esm/loader');
 const {
   hasUncaughtExceptionCaptureCallback,
@@ -26,13 +25,6 @@ exports.initializeImportMetaObject = function(wrap, meta) {
 };
 
 exports.importModuleDynamicallyCallback = async function(wrap, specifier) {
-  assert(calledInitialize === true || !userLoader);
-  if (!calledInitialize) {
-    process.emitWarning(
-      'The ESM module loader is experimental.',
-      'ExperimentalWarning', undefined);
-    calledInitialize = true;
-  }
   const { callbackMap } = internalBinding('module_wrap');
   if (callbackMap.has(wrap)) {
     const { importModuleDynamically } = callbackMap.get(wrap);
@@ -47,15 +39,7 @@ exports.importModuleDynamicallyCallback = async function(wrap, specifier) {
 let ESMLoader = new Loader();
 exports.ESMLoader = ESMLoader;
 
-let calledInitialize = false;
-async function initializeLoader(emitWarning) {
-  assert(calledInitialize === false);
-  if (emitWarning) {
-    process.emitWarning(
-      'The ESM module loader is experimental.',
-      'ExperimentalWarning', undefined);
-  }
-  calledInitialize = true;
+async function initializeLoader() {
   if (!userLoader)
     return;
   let cwd;
@@ -78,9 +62,9 @@ async function initializeLoader(emitWarning) {
   })();
 }
 
-exports.loadESM = async function loadESM(callback, emitWarning = true) {
+exports.loadESM = async function loadESM(callback) {
   try {
-    await initializeLoader(emitWarning);
+    await initializeLoader();
     await callback(ESMLoader);
   } catch (err) {
     if (hasUncaughtExceptionCaptureCallback()) {

diff --git a/test/es-module/test-esm-dynamic-import.js b/test/es-module/test-esm-dynamic-import.js
@@ -38,9 +38,6 @@ function expectFsNamespace(result) {
 // For direct use of import expressions inside of CJS or ES modules, including
 // via eval, all kinds of specifiers should work without issue.
 (function testScriptOrModuleImport() {
-  common.expectWarning('ExperimentalWarning',
-                       'The ESM module loader is experimental.');
-
   // Importing another file, both direct & via eval
   // expectOkNamespace(import(relativePath));
   expectOkNamespace(eval(`import("${relativePath}")`));

diff --git a/test/es-module/test-esm-nowarn-exports.mjs b/test/es-module/test-esm-nowarn-exports.mjs
@@ -16,7 +16,7 @@ child.stderr.on('data', (data) => {
 child.on('close', (code, signal) => {
   strictEqual(code, 0);
   strictEqual(signal, null);
-  ok(stderr.toString().includes(
+  ok(!stderr.toString().includes(
     'ExperimentalWarning: The ESM module loader is experimental'
   ));
   ok(!stderr.toString().includes(

diff --git a/test/message/async_error_sync_esm.out b/test/message/async_error_sync_esm.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 Error: test
     at one (*fixtures*async-error.js:4:9)
     at two (*fixtures*async-error.js:17:9)

diff --git a/test/message/esm_display_syntax_error.out b/test/message/esm_display_syntax_error.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 file:///*/test/message/esm_display_syntax_error.mjs:2
 await async () => 0;
 ^^^^^

diff --git a/test/message/esm_display_syntax_error_import.out b/test/message/esm_display_syntax_error_import.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 file:///*/test/message/esm_display_syntax_error_import.mjs:5
   notfound
   ^^^^^^^^

diff --git a/test/message/esm_display_syntax_error_import_module.out b/test/message/esm_display_syntax_error_import_module.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 file:///*/test/fixtures/es-module-loaders/syntax-error-import.mjs:1
 import { foo, notfound } from './module-named-exports.mjs';
               ^^^^^^^^

diff --git a/test/message/esm_display_syntax_error_module.out b/test/message/esm_display_syntax_error_module.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 file:///*/test/fixtures/es-module-loaders/syntax-error.mjs:2
 await async () => 0;
 ^^^^^

diff --git a/test/message/esm_loader_not_found.out b/test/message/esm_loader_not_found.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 (node:*) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
 internal/process/esm_loader.js:*
     internalBinding('errors').triggerUncaughtException(

diff --git a/test/message/esm_loader_not_found_cjs_hint_bare.out b/test/message/esm_loader_not_found_cjs_hint_bare.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 internal/process/esm_loader.js:*
     internalBinding('errors').triggerUncaughtException(
                               ^

diff --git a/test/message/esm_loader_not_found_cjs_hint_relative.out b/test/message/esm_loader_not_found_cjs_hint_relative.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 (node:*) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
 internal/process/esm_loader.js:*
     internalBinding('errors').triggerUncaughtException(

diff --git a/test/message/esm_loader_syntax_error.out b/test/message/esm_loader_syntax_error.out
@@ -1,4 +1,3 @@
-(node:*) ExperimentalWarning: The ESM module loader is experimental.
 (node:*) ExperimentalWarning: --experimental-loader is an experimental feature. This feature could change at any time
 file://*/test/fixtures/es-module-loaders/syntax-error.mjs:2
 await async () => 0;