From dcb6993d6c377c5013051e4c894e90a49cda5e5b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Pavel=20Kol=C3=A1=C5=99?= <pavel@learnlife.com>
Date: Wed, 12 May 2021 20:52:13 +0200
Subject: [PATCH] Fix: no-unused-vars 1 arg arrow fns (#74)

---
 packages/autofix/lib/rules/no-unused-vars.js  | 18 ++++++++++++--
 .../autofix/tests/lib/rules/no-unused-vars.js | 24 +++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)

diff --git a/packages/autofix/lib/rules/no-unused-vars.js b/packages/autofix/lib/rules/no-unused-vars.js
index 1103470..55e6130 100644
--- a/packages/autofix/lib/rules/no-unused-vars.js
+++ b/packages/autofix/lib/rules/no-unused-vars.js
@@ -116,18 +116,32 @@ module.exports = ruleComposer.mapReports(
                             return fixer.insertTextBefore(node, prefix);
                         }
                         case "after-used": {
+                            const tokenBefore = sourceCode.getTokenBefore(node)
+                            const tokenAfter = sourceCode.getTokenAfter(node)
+
+                            if (
+                              parent.params.length === 1 &&
+                              !(tokenBefore && tokenBefore.value === '(') &&
+                              !(tokenAfter && tokenAfter.value === ')')
+                            ) {
+                                return [
+                                  fixer.insertTextBefore(node, '('),
+                                  fixer.insertTextAfter(node, ')'),
+                                  fixer.remove(node)
+                                ]
+                            }
+
                             const comma = sourceCode.getTokenBefore(node, commaFilter);
 
                             if (comma && comma.range && grand.range && comma.range[0] >= grand.range[0]) {
                                 return [fixer.remove(comma), fixer.remove(node)];
                             }
-                            const commaAfter = sourceCode.getTokenAfter(node, commaFilter);
+                            const commaAfter = sourceCode.getTokenAfter(node, commaFilter);
 
                             if (commaAfter && commaAfter.range && grand.range && commaAfter.range[1] <= grand.range[1]) {
                                 return [fixer.remove(node), fixer.remove(commaAfter)];
                             }
 
-
                             return [fixer.remove(node)];
                         }
                         default:
diff --git a/packages/autofix/tests/lib/rules/no-unused-vars.js b/packages/autofix/tests/lib/rules/no-unused-vars.js
index 01ac803..25c793b 100644
--- a/packages/autofix/tests/lib/rules/no-unused-vars.js
+++ b/packages/autofix/tests/lib/rules/no-unused-vars.js
@@ -237,6 +237,30 @@ ruleTester.run("no-unused-vars", rule, {
                 argsIgnorePattern: "^_"
             }]
         },
+        {
+            code: "const foo = (a) => {}; foo();",
+            output: "const foo = () => {}; foo();",
+            parserOptions: { ecmaVersion: 2018 },
+            errors: [
+              { type: "Identifier" }
+            ],
+            options: [{
+                args: "after-used",
+                argsIgnorePattern: "^_",
+            }]
+        },
+        {
+            code: "const foo = a => {}; foo();",
+            output: "const foo = () => {}; foo();",
+            parserOptions: { ecmaVersion: 2018 },
+            errors: [
+              { type: "Identifier" }
+            ],
+            options: [{
+                args: "after-used",
+                argsIgnorePattern: "^_",
+            }]
+        },
         {
             code: "function foo(a, b, c){console.log(b);}; foo(1, 2, 3);",
             output: "function foo(_a, b, _c){console.log(b);}; foo(1, 2, 3);",