From 72a586121a22111c8540920c616a31ce21f764f0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Thu, 30 Mar 2023 19:06:39 +0200
Subject: [PATCH] Align behavior with TS

---
 .../src/plugins/typescript/index.ts           | 14 ++--------
 .../export/equals-in-script/output.json       |  3 +++
 .../export/equals-in-unambiguous/output.json  |  2 +-
 .../import/equals-in-script/output.json       |  3 +++
 .../equals-require-in-script/output.json      |  3 +++
 .../equals-require-in-unambiguous/output.json |  2 +-
 .../src/index.ts                              | 26 ++++++++++++-------
 .../fixtures/exports/export=-script/input.ts  |  1 -
 .../exports/export=-script/options.json       |  3 ---
 .../fixtures/exports/export=-script/output.js |  1 -
 .../fixtures/exports/export=/options.json     |  2 +-
 .../imports/import=-module/options.json       |  2 +-
 .../fixtures/imports/import=-script/input.ts  |  2 --
 .../imports/import=-script/options.json       |  3 ---
 .../fixtures/imports/import=-script/output.js |  2 --
 15 files changed, 31 insertions(+), 38 deletions(-)
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/input.ts
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/options.json
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/output.js
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/input.ts
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/options.json
 delete mode 100644 packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/output.js

diff --git a/packages/babel-parser/src/plugins/typescript/index.ts b/packages/babel-parser/src/plugins/typescript/index.ts
index df97882b7729..665df7ab23f3 100644
--- a/packages/babel-parser/src/plugins/typescript/index.ts
+++ b/packages/babel-parser/src/plugins/typescript/index.ts
@@ -2017,6 +2017,7 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
       // For compatibility to estree we cannot call parseLiteral directly here
       node.expression = super.parseExprAtom() as N.StringLiteral;
       this.expect(tt.parenR);
+      this.sawUnambiguousESM = true;
       return this.finishNode(node, "TSExternalModuleReference");
     }
 
@@ -2711,18 +2712,6 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
     */
     checkDuplicateExports() {}
 
-    assertModuleNodeAllowed(node: N.Node): void {
-      if (
-        node.type === "TSImportEqualsDeclaration" ||
-        node.type === "TSExportAssignment"
-      ) {
-        // `import ... =` and `export =` are allowed in scripts,
-        // since they are used for CommonJS.
-        return;
-      }
-      super.assertModuleNodeAllowed(node);
-    }
-
     parseImport(
       node: Undone<N.ImportDeclaration | N.TsImportEqualsDeclaration>,
     ): N.AnyImport {
@@ -2800,6 +2789,7 @@ export default (superClass: ClassWithMixin<typeof Parser, IJSXParserMixin>) =>
         const assign = node as Undone<N.TsExportAssignment>;
         assign.expression = super.parseExpression();
         this.semicolon();
+        this.sawUnambiguousESM = true;
         return this.finishNode(assign, "TSExportAssignment");
       } else if (this.eatContextual(tt._as)) {
         // `export as namespace A;`
diff --git a/packages/babel-parser/test/fixtures/typescript/export/equals-in-script/output.json b/packages/babel-parser/test/fixtures/typescript/export/equals-in-script/output.json
index 4435b69c7622..a49b3540c5dd 100644
--- a/packages/babel-parser/test/fixtures/typescript/export/equals-in-script/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/export/equals-in-script/output.json
@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":11,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":11,"index":11}},
+  "errors": [
+    "SyntaxError: 'import' and 'export' may appear only with 'sourceType: \"module\"' (1:0)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":11,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":11,"index":11}},
diff --git a/packages/babel-parser/test/fixtures/typescript/export/equals-in-unambiguous/output.json b/packages/babel-parser/test/fixtures/typescript/export/equals-in-unambiguous/output.json
index 4435b69c7622..9f13e9e0bae5 100644
--- a/packages/babel-parser/test/fixtures/typescript/export/equals-in-unambiguous/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/export/equals-in-unambiguous/output.json
@@ -4,7 +4,7 @@
   "program": {
     "type": "Program",
     "start":0,"end":11,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":11,"index":11}},
-    "sourceType": "script",
+    "sourceType": "module",
     "interpreter": null,
     "body": [
       {
diff --git a/packages/babel-parser/test/fixtures/typescript/import/equals-in-script/output.json b/packages/babel-parser/test/fixtures/typescript/import/equals-in-script/output.json
index f89c0c3c37b3..6d116ee43624 100644
--- a/packages/babel-parser/test/fixtures/typescript/import/equals-in-script/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/import/equals-in-script/output.json
@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
+  "errors": [
+    "SyntaxError: 'import' and 'export' may appear only with 'sourceType: \"module\"' (1:0)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":15,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":15,"index":15}},
diff --git a/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-script/output.json b/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-script/output.json
index 8a8fdd743052..1d87684dbe32 100644
--- a/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-script/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-script/output.json
@@ -1,6 +1,9 @@
 {
   "type": "File",
   "start":0,"end":24,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":24,"index":24}},
+  "errors": [
+    "SyntaxError: 'import' and 'export' may appear only with 'sourceType: \"module\"' (1:0)"
+  ],
   "program": {
     "type": "Program",
     "start":0,"end":24,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":24,"index":24}},
diff --git a/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-unambiguous/output.json b/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-unambiguous/output.json
index 8a8fdd743052..19b29f5d027f 100644
--- a/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-unambiguous/output.json
+++ b/packages/babel-parser/test/fixtures/typescript/import/equals-require-in-unambiguous/output.json
@@ -4,7 +4,7 @@
   "program": {
     "type": "Program",
     "start":0,"end":24,"loc":{"start":{"line":1,"column":0,"index":0},"end":{"line":1,"column":24,"index":24}},
-    "sourceType": "script",
+    "sourceType": "module",
     "interpreter": null,
     "body": [
       {
diff --git a/packages/babel-plugin-transform-typescript/src/index.ts b/packages/babel-plugin-transform-typescript/src/index.ts
index bcb9f6c7ff20..4375e1560bb6 100644
--- a/packages/babel-plugin-transform-typescript/src/index.ts
+++ b/packages/babel-plugin-transform-typescript/src/index.ts
@@ -1,6 +1,6 @@
 import { declare } from "@babel/helper-plugin-utils";
 import syntaxTypeScript from "@babel/plugin-syntax-typescript";
-import type { types as t } from "@babel/core";
+import type { PluginPass, types as t } from "@babel/core";
 import { injectInitialization } from "@babel/helper-create-class-features-plugin";
 import type { Binding, NodePath, Scope } from "@babel/traverse";
 import type { Options as SyntaxOptions } from "@babel/plugin-syntax-typescript";
@@ -78,17 +78,18 @@ function safeRemove(path: NodePath) {
   path.opts.noScope = false;
 }
 
-function assertCjsModuleIsScript(
+function assertCjsTransformEnabled(
   path: NodePath,
+  pass: PluginPass,
   wrong: string,
   suggestion: string,
   extra: string = "",
 ): void {
-  const programParent = path.find(p => p.isProgram()) as NodePath<t.Program>;
-  if (programParent.node.sourceType !== "script") {
+  if (pass.get("@babel/plugin-transform-modules-*") !== "commonjs") {
     throw path.buildCodeFrameError(
-      `\`${wrong}\` is only supported when "sourceType" is "script".\n` +
-        `Please consider using \`${suggestion}\`${extra}.`,
+      `\`${wrong}\` is only supported when compiling modules to CommonJS.\n` +
+        `Please consider using \`${suggestion}\`${extra}, or add ` +
+        `@babel/plugin-transform-modules-commonjs to your Babel config.`,
     );
   }
 }
@@ -589,15 +590,19 @@ export default declare((api, opts: Options) => {
         }
       },
 
-      TSImportEqualsDeclaration(path: NodePath<t.TSImportEqualsDeclaration>) {
+      TSImportEqualsDeclaration(
+        path: NodePath<t.TSImportEqualsDeclaration>,
+        pass,
+      ) {
         const { id, moduleReference } = path.node;
 
         let init: t.Expression;
         let varKind: "var" | "const";
         if (t.isTSExternalModuleReference(moduleReference)) {
           // import alias = require('foo');
-          assertCjsModuleIsScript(
+          assertCjsTransformEnabled(
             path,
+            pass,
             `import ${id.name} = require(...);`,
             `import ${id.name} from '...';`,
             " alongside Typescript's --allowSyntheticDefaultImports option",
@@ -618,9 +623,10 @@ export default declare((api, opts: Options) => {
         path.scope.registerDeclaration(path);
       },
 
-      TSExportAssignment(path) {
-        assertCjsModuleIsScript(
+      TSExportAssignment(path, pass) {
+        assertCjsTransformEnabled(
           path,
+          pass,
           `export = <value>;`,
           `export default <value>;`,
         );
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/input.ts
deleted file mode 100644
index fbedae645eb3..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/input.ts
+++ /dev/null
@@ -1 +0,0 @@
-export = 0;
\ No newline at end of file
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/options.json
deleted file mode 100644
index b412ffe6712f..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/options.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "sourceType": "script"
-}
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/output.js
deleted file mode 100644
index d5b2e8bb3efb..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=-script/output.js
+++ /dev/null
@@ -1 +0,0 @@
-module.exports = 0;
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=/options.json
index e2376e518413..a4af08a4d481 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=/options.json
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/exports/export=/options.json
@@ -1,3 +1,3 @@
 {
-  "throws": "`export = <value>;` is only supported when \"sourceType\" is \"script\".\nPlease consider using `export default <value>;`"
+  "throws": "`export = <value>;` is only supported when compiling modules to CommonJS.\nPlease consider using `export default <value>;`, or add @babel/plugin-transform-modules-commonjs to your Babel config."
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-module/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-module/options.json
index 8f13c717fc76..eb23daa9d797 100644
--- a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-module/options.json
+++ b/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-module/options.json
@@ -1,4 +1,4 @@
 {
   "sourceType": "module",
-  "throws": "`import lib = require(...);` is only supported when \"sourceType\" is \"script\".\nPlease consider using `import lib from '...';` alongside Typescript's --allowSyntheticDefaultImports option."
+  "throws": "`import lib = require(...);` is only supported when compiling modules to CommonJS.\nPlease consider using `import lib from '...';` alongside Typescript's --allowSyntheticDefaultImports option, or add @babel/plugin-transform-modules-commonjs to your Babel config."
 }
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/input.ts b/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/input.ts
deleted file mode 100644
index dc8b049669b3..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/input.ts
+++ /dev/null
@@ -1,2 +0,0 @@
-import lib = require("lib");
-lib();
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/options.json b/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/options.json
deleted file mode 100644
index b412ffe6712f..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/options.json
+++ /dev/null
@@ -1,3 +0,0 @@
-{
-  "sourceType": "script"
-}
diff --git a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/output.js b/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/output.js
deleted file mode 100644
index 2ddbce589436..000000000000
--- a/packages/babel-plugin-transform-typescript/test/fixtures/imports/import=-script/output.js
+++ /dev/null
@@ -1,2 +0,0 @@
-const lib = require("lib");
-lib();