prefer-default-parameters: Fix non-iterable visitorKeys (#1013)

Co-authored-by: fisker <lionkay@gmail.com>

rules/prefer-default-parameters.js

@@ -1,4 +1,5 @@
 'use strict';
+const eslintVisitorKeys = require('eslint-visitor-keys');
 const {findVariable} = require('eslint-utils');
 const getDocumentationUrl = require('./utils/get-documentation-url');
 
@@ -33,7 +34,12 @@ const containsCallExpression = (source, node) => {
 		return true;
 	}
 
-	for (const key of source.visitorKeys[node.type]) {
+	// The Babel AST doesn't have visitor keys for certain types of nodes
+	// Use `eslint-visitor-keys` in those cases
+	// TODO: Remove this when we drop support for `babel-eslint` #1040
+	const keys = source.visitorKeys[node.type] || eslintVisitorKeys.KEYS[node.type];
+
+	for (const key of keys) {
 		const value = node[key];
 
 		if (Array.isArray(value)) {

test/prefer-default-parameters.js

@@ -1,13 +1,5 @@
-import test from 'ava';
-import avaRuleTester from 'eslint-ava-rule-tester';
 import {outdent} from 'outdent';
-import rule from '../rules/prefer-default-parameters.js';
-
-const ruleTester = avaRuleTester(test, {
-	parserOptions: {
-		ecmaVersion: 2020
-	}
-});
+import {test} from './utils/test.js';
 
 const invalidTestCase = ({code, suggestions}) => {
 	if (!suggestions) {
@@ -33,7 +25,7 @@ const invalidTestCase = ({code, suggestions}) => {
 	};
 };
 
-ruleTester.run('prefer-default-parameters', rule, {
+test({
 	valid: [
 		'function abc(foo = { bar: 123 }) { }',
 		'function abc({ bar } = { bar: 123 }) { }',
@@ -655,3 +647,28 @@ ruleTester.run('prefer-default-parameters', rule, {
 		})
 	]
 });
+
+test.babelLegacy({
+	valid: [
+		// These tests verify that the fallback to `eslint-visitor-keys` is working correctly
+		outdent`
+			function abc(foo, bar) {
+				const { baz, ...rest } = bar;
+				foo = foo || 123;
+			}
+		`,
+		outdent`
+			function abc(foo, bar) {
+				const baz = foo?.bar;
+				foo = foo || 123;
+			}
+		`,
+		outdent`
+			function abc(foo, bar) {
+				import('foo');
+				foo = foo || 123;
+			}
+		`
+	],
+	invalid: []
+});