lib,test: improves ERR_REQUIRE_ESM message

PR-URL: #30694 Fixes: #30599 Reviewed-By: Guy Bedford <guybedford@gmail.com>
nodejs · Dec 9, 2019 · 94f237e · 94f237e
1 parent 30756e3
commit 94f237e
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Showing 4 changed files with 35 additions and 28 deletions.
diff --git a/lib/internal/errors.js b/lib/internal/errors.js
@@ -1123,7 +1123,26 @@ E('ERR_OUT_OF_RANGE',
     msg += ` It must be ${range}. Received ${received}`;
     return msg;
   }, RangeError);
-E('ERR_REQUIRE_ESM', 'Must use import to load ES Module: %s', Error);
+E('ERR_REQUIRE_ESM',
+  (filename, parentPath = null, packageJsonPath = null) => {
+    let msg = `Must use import to load ES Module: ${filename}`;
+    if (parentPath && packageJsonPath) {
+      const path = require('path');
+      const basename = path.basename(filename) === path.basename(parentPath) ?
+        filename : path.basename(filename);
+      msg +=
+        '\nrequire() of ES modules is not supported.\nrequire() of ' +
+        `${filename} ${parentPath ? `from ${parentPath} ` : ''}` +
+        'is an ES module file as it is a .js file whose nearest parent ' +
+        'package.json contains "type": "module" which defines all .js ' +
+        'files in that package scope as ES modules.\nInstead rename ' +
+        `${basename} to end in .cjs, change the requiring code to use ` +
+        'import(), or remove "type": "module" from ' +
+        `${packageJsonPath}.\n`;
+      return msg;
+    }
+    return msg;
+  }, Error);
 E('ERR_SCRIPT_EXECUTION_INTERRUPTED',
   'Script execution was interrupted by `SIGINT`', Error);
 E('ERR_SERVER_ALREADY_LISTEN',

diff --git a/lib/internal/modules/cjs/loader.js b/lib/internal/modules/cjs/loader.js
@@ -1139,33 +1139,14 @@ Module.prototype._compile = function(content, filename) {
 };
 
 // Native extension for .js
-let warnRequireESM = true;
 Module._extensions['.js'] = function(module, filename) {
   if (filename.endsWith('.js')) {
     const pkg = readPackageScope(filename);
+    // Function require shouldn't be used in ES modules.
     if (pkg && pkg.data && pkg.data.type === 'module') {
-      if (warnRequireESM) {
-        const parentPath = module.parent && module.parent.filename;
-        const basename = parentPath &&
-            path.basename(filename) === path.basename(parentPath) ?
-          filename : path.basename(filename);
-        process.emitWarning(
-          'require() of ES modules is not supported.\nrequire() of ' +
-          `${filename} ${parentPath ? `from ${module.parent.filename} ` : ''}` +
-          'is an ES module file as it is a .js file whose nearest parent ' +
-          'package.json contains "type": "module" which defines all .js ' +
-          'files in that package scope as ES modules.\nInstead rename ' +
-          `${basename} to end in .cjs, change the requiring code to use ` +
-          'import(), or remove "type": "module" from ' +
-          `${path.resolve(pkg.path, 'package.json')}.`,
-          undefined,
-          undefined,
-          undefined,
-          true
-        );
-        warnRequireESM = false;
-      }
-      throw new ERR_REQUIRE_ESM(filename);
+      const parentPath = module.parent && module.parent.filename;
+      const packageJsonPath = path.resolve(pkg.path, 'package.json');
+      throw new ERR_REQUIRE_ESM(filename, parentPath, packageJsonPath);
     }
   }
   const content = fs.readFileSync(filename, 'utf8');

diff --git a/test/es-module/test-cjs-esm-warn.js b/test/es-module/test-cjs-esm-warn.js
@@ -26,15 +26,19 @@ child.on('close', common.mustCall((code, signal) => {
   assert.strictEqual(code, 1);
   assert.strictEqual(signal, null);
 
-  assert.ok(stderr.startsWith(`(node:${child.pid}) Warning: ` +
-    'require() of ES modules is not supported.\nrequire() of ' +
+  assert.ok(stderr.indexOf(
+    `Error [ERR_REQUIRE_ESM]: Must use import to load ES Module: ${required}` +
+    '\nrequire() of ES modules is not supported.\nrequire() of ' +
     `${required} from ${requiring} ` +
     'is an ES module file as it is a .js file whose nearest parent ' +
     'package.json contains "type": "module" which defines all .js ' +
     'files in that package scope as ES modules.\nInstead rename ' +
     `${basename} to end in .cjs, change the requiring code to use ` +
     'import(), or remove "type": "module" from ' +
-    `${pjson}.\n`));
+    `${pjson}.\n`) !== -1);
   assert.ok(stderr.indexOf(
     'Error [ERR_REQUIRE_ESM]: Must use import to load ES Module') !== -1);
+
+  assert.strictEqual(
+    stderr.match(/Must use import to load ES Module/g).length, 1);
 }));
diff --git a/test/es-module/test-esm-type-flag-errors.js b/test/es-module/test-esm-type-flag-errors.js
@@ -27,7 +27,10 @@ try {
   require('../fixtures/es-modules/package-type-module/index.js');
   assert.fail('Expected CJS to fail loading from type: module package.');
 } catch (e) {
-  assert(e.toString().match(/Error \[ERR_REQUIRE_ESM\]: Must use import to load ES Module:/));
+  assert.strictEqual(e.name, 'Error');
+  assert.strictEqual(e.code, 'ERR_REQUIRE_ESM');
+  assert(e.toString().match(/Must use import to load ES Module/g));
+  assert(e.message.match(/Must use import to load ES Module/g));
 }
 
 function expect(opt = '', inputFile, want, wantsError = false) {