feat(eslint-plugin): [prefer-optional-chain] added option to convert …

…to suggestion fixer (#1965)
typescript-eslint · May 4, 2020 · 2f0824b · 2f0824b
1 parent 7f3fba3
commit 2f0824b
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diff --git a/packages/eslint-plugin/docs/rules/prefer-optional-chain.md b/packages/eslint-plugin/docs/rules/prefer-optional-chain.md
@@ -70,6 +70,21 @@ foo?.a?.b?.method?.();
 foo?.a?.b?.c?.d?.e;
 ```
 
+## Options
+
+The rule accepts an options object with the following properties:
+
+```ts
+type Options = {
+  // if true, the rule will only provide suggested fixes instead of automatically modifying code
+  suggestInsteadOfAutofix?: boolean;
+};
+
+const defaults = {
+  suggestInsteadOfAutofix: false,
+};
+```
+
 ## When Not To Use It
 
 If you are not using TypeScript 3.7 (or greater), then you will not be able to use this rule, as the operator is not supported.

diff --git a/packages/eslint-plugin/src/rules/prefer-optional-chain.ts b/packages/eslint-plugin/src/rules/prefer-optional-chain.ts
@@ -1,6 +1,7 @@
 import {
   AST_NODE_TYPES,
   TSESTree,
+  TSESLint,
 } from '@typescript-eslint/experimental-utils';
 import * as util from '../util';
 
@@ -29,7 +30,16 @@ The AST will look like this:
   right: foo.bar.baz.buzz
 }
 */
-export default util.createRule({
+
+type Options = [
+  {
+    suggestInsteadOfAutofix?: boolean;
+  },
+];
+
+type MessageIds = 'preferOptionalChain' | 'optionalChainSuggest';
+
+export default util.createRule<Options, MessageIds>({
   name: 'prefer-optional-chain',
   meta: {
     type: 'suggestion',
@@ -43,11 +53,26 @@ export default util.createRule({
     messages: {
       preferOptionalChain:
         "Prefer using an optional chain expression instead, as it's more concise and easier to read.",
+      optionalChainSuggest: 'Change to an optional chain.',
     },
-    schema: [],
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          suggestInsteadOfAutofix: {
+            type: 'boolean',
+          },
+        },
+        additionalProperties: false,
+      },
+    ],
   },
-  defaultOptions: [],
-  create(context) {
+  defaultOptions: [
+    {
+      suggestInsteadOfAutofix: false,
+    },
+  ],
+  create(context, [options]) {
     const sourceCode = context.getSourceCode();
     return {
       [[
@@ -163,13 +188,28 @@ export default util.createRule({
             } ${sourceCode.getText(previous.right.right)}`;
           }
 
-          context.report({
-            node: previous,
-            messageId: 'preferOptionalChain',
-            fix(fixer) {
-              return fixer.replaceText(previous, optionallyChainedCode);
-            },
-          });
+          if (!options.suggestInsteadOfAutofix) {
+            context.report({
+              node: previous,
+              messageId: 'preferOptionalChain',
+              fix(fixer) {
+                return fixer.replaceText(previous, optionallyChainedCode);
+              },
+            });
+          } else {
+            context.report({
+              node: previous,
+              messageId: 'preferOptionalChain',
+              suggest: [
+                {
+                  messageId: 'optionalChainSuggest',
+                  fix: (fixer): TSESLint.RuleFix[] => [
+                    fixer.replaceText(previous, optionallyChainedCode),
+                  ],
+                },
+              ],
+            });
+          }
         }
       },
     };

diff --git a/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts b/packages/eslint-plugin/tests/rules/prefer-optional-chain.test.ts
@@ -291,5 +291,56 @@ ruleTester.run('prefer-optional-chain', rule, {
         },
       ],
     },
+    // using suggestion instead of autofix
+    {
+      code:
+        'foo && foo.bar != null && foo.bar.baz !== undefined && foo.bar.baz.buzz;',
+      options: [
+        {
+          suggestInsteadOfAutofix: true,
+        },
+      ],
+      output: null,
+      errors: [
+        {
+          messageId: 'preferOptionalChain',
+          line: 1,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'optionalChainSuggest',
+              output: 'foo?.bar?.baz?.buzz;',
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: 'foo && foo.bar(baz => <This Requires Spaces />);',
+      options: [
+        {
+          suggestInsteadOfAutofix: true,
+        },
+      ],
+      output: null,
+      errors: [
+        {
+          messageId: 'preferOptionalChain',
+          line: 1,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'optionalChainSuggest',
+              output: 'foo?.bar(baz => <This Requires Spaces />);',
+            },
+          ],
+        },
+      ],
+      parserOptions: {
+        ecmaFeatures: {
+          jsx: true,
+        },
+      },
+    },
   ],
 });