From 8e66bf744448b8a3c64bf32c5ba893d16fa7f3ac Mon Sep 17 00:00:00 2001
From: Bryan Mishkin <698306+bmish@users.noreply.github.com>
Date: Sun, 10 Jul 2022 22:08:53 -0400
Subject: [PATCH] fix: detect rules with TypeScript `export = rule` syntax
 (#267)

---
 lib/utils.js       |  9 +++++--
 tests/lib/utils.js | 62 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 69 insertions(+), 2 deletions(-)

diff --git a/lib/utils.js b/lib/utils.js
index 5b744964..d2bc6505 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -121,8 +121,13 @@ function isTypeScriptRuleHelper(node) {
 function getRuleExportsESM(ast, scopeManager) {
   return (
     ast.body
-      .filter((statement) => statement.type === 'ExportDefaultDeclaration')
-      .map((statement) => statement.declaration)
+      .filter((statement) =>
+        [
+          'ExportDefaultDeclaration', // export default rule;
+          'TSExportAssignment', // export = rule;
+        ].includes(statement.type)
+      )
+      .map((statement) => statement.declaration || statement.expression)
       // eslint-disable-next-line unicorn/prefer-object-from-entries
       .reduce((currentExports, node) => {
         if (node.type === 'ObjectExpression') {
diff --git a/tests/lib/utils.js b/tests/lib/utils.js
index c6ecb382..66e1b02d 100644
--- a/tests/lib/utils.js
+++ b/tests/lib/utils.js
@@ -119,6 +119,9 @@ describe('utils', () => {
         'const notRule = foo(); export default notRule;',
         'const notRule = function(){}; export default notRule;',
         'const notRule = {}; export default notRule;',
+        'const notRule = {}; export = notRule;',
+        'const notRule: Rule.RuleModule = {}; export = notRule;',
+        'export = {};',
       ].forEach((noRuleCase) => {
         it(`returns null for ${noRuleCase}`, () => {
           const ast = typescriptEslintParser.parse(noRuleCase, {
@@ -188,6 +191,65 @@ describe('utils', () => {
             isNewStyle: true,
           },
 
+        // No helper.
+        'export default { create() {}, meta: {} };': {
+          create: { type: 'FunctionExpression' },
+          meta: { type: 'ObjectExpression' },
+          isNewStyle: true,
+        },
+        // No helper, `export =` syntax.
+        'export = { create() {}, meta: {} };': {
+          create: { type: 'FunctionExpression' },
+          meta: { type: 'ObjectExpression' },
+          isNewStyle: true,
+        },
+        // No helper, variable.
+        'const rule = { create() {}, meta: {} }; export default rule;': {
+          create: { type: 'FunctionExpression' },
+          meta: { type: 'ObjectExpression' },
+          isNewStyle: true,
+        },
+        // no helper, variable with type.
+        'const rule: Rule.RuleModule = { create() {}, meta: {} }; export default rule;':
+          {
+            create: { type: 'FunctionExpression' },
+            meta: { type: 'ObjectExpression' },
+            isNewStyle: true,
+          },
+        // No helper, variable, `export =` syntax.
+        'const rule = { create() {}, meta: {} }; export = rule;': {
+          create: { type: 'FunctionExpression' },
+          meta: { type: 'ObjectExpression' },
+          isNewStyle: true,
+        },
+        // No helper, variable with type, `export =` syntax.
+        'const rule: Rule.RuleModule = { create() {}, meta: {} }; export = rule;':
+          {
+            create: { type: 'FunctionExpression' },
+            meta: { type: 'ObjectExpression' },
+            isNewStyle: true,
+          },
+        // Helper, variable, `export =` syntax.
+        'const rule = createESLintRule({ create() {}, meta: {} }); export = rule;':
+          {
+            create: { type: 'FunctionExpression' },
+            meta: { type: 'ObjectExpression' },
+            isNewStyle: true,
+          },
+        // Helper, variable with type, `export =` syntax.
+        'const rule: Rule.RuleModule = createESLintRule({ create() {}, meta: {} }); export = rule;':
+          {
+            create: { type: 'FunctionExpression' },
+            meta: { type: 'ObjectExpression' },
+            isNewStyle: true,
+          },
+        // Helper, `export =` syntax.
+        'export = createESLintRule({ create() {}, meta: {} });': {
+          create: { type: 'FunctionExpression' },
+          meta: { type: 'ObjectExpression' },
+          isNewStyle: true,
+        },
+
         // Util function with "{} as const".
         'export default createESLintRule({ create() {}, meta: {} as const });':
           {