fix(eslint-plugin): [array-type] parenthesize ReadonlyArray fix (typescript-eslint#2747)

a-tarasyuk · web-flow · commit 83385ac351f4 · 2020-11-08T13:10:01.000-08:00
diff --git a/packages/eslint-plugin/src/rules/array-type.ts b/packages/eslint-plugin/src/rules/array-type.ts
@@ -244,7 +244,14 @@ export default util.createRule<Options, MessageIds>({
         }
 
         const type = typeParams[0];
-        const parens = typeNeedsParentheses(type);
+        const typeParens = typeNeedsParentheses(type);
+        const parentParens =
+          readonlyPrefix && node.parent?.type === AST_NODE_TYPES.TSArrayType;
+
+        const start = `${parentParens ? '(' : ''}${readonlyPrefix}${
+          typeParens ? '(' : ''
+        }`;
+        const end = `${typeParens ? ')' : ''}[]${parentParens ? ')' : ''}`;
 
         context.report({
           node,
@@ -254,14 +261,8 @@ export default util.createRule<Options, MessageIds>({
           },
           fix(fixer) {
             return [
-              fixer.replaceTextRange(
-                [node.range[0], type.range[0]],
-                `${readonlyPrefix}${parens ? '(' : ''}`,
-              ),
-              fixer.replaceTextRange(
-                [type.range[1], node.range[1]],
-                parens ? ')[]' : '[]',
-              ),
+              fixer.replaceTextRange([node.range[0], type.range[0]], start),
+              fixer.replaceTextRange([type.range[1], node.range[1]], end),
             ];
           },
         });
diff --git a/packages/eslint-plugin/tests/rules/array-type.test.ts b/packages/eslint-plugin/tests/rules/array-type.test.ts
@@ -1648,6 +1648,19 @@ interface FooInterface {
         },
       ],
     },
+    {
+      code: 'type Foo = ReadonlyArray<object>[];',
+      output: 'type Foo = (readonly object[])[];',
+      options: [{ default: 'array' }],
+      errors: [
+        {
+          messageId: 'errorStringArray',
+          data: { type: 'object' },
+          line: 1,
+          column: 12,
+        },
+      ],
+    },
   ],
 });
 
