From bc2c0fd7898d21bdde268987bcc7cc776bc768ac Mon Sep 17 00:00:00 2001
From: auvred <aauvred@gmail.com>
Date: Thu, 4 Jan 2024 10:54:00 +0000
Subject: [PATCH 1/2] fix(eslint-plugin): [no-non-null-assertion] provide valid
 fix when member access is on next line

---
 .../src/rules/no-non-null-assertion.ts        | 48 ++++++------
 .../tests/rules/no-non-null-assertion.test.ts | 74 ++++++++++++++++++-
 2 files changed, 94 insertions(+), 28 deletions(-)

diff --git a/packages/eslint-plugin/src/rules/no-non-null-assertion.ts b/packages/eslint-plugin/src/rules/no-non-null-assertion.ts
index 25617ca41f25..f80d0ee00914 100644
--- a/packages/eslint-plugin/src/rules/no-non-null-assertion.ts
+++ b/packages/eslint-plugin/src/rules/no-non-null-assertion.ts
@@ -29,33 +29,19 @@ export default createRule<[], MessageIds>({
     return {
       TSNonNullExpression(node): void {
         const suggest: TSESLint.ReportSuggestionArray<MessageIds> = [];
-        function convertTokenToOptional(
-          replacement: '?.' | '?',
-        ): TSESLint.ReportFixFunction {
-          return (fixer: TSESLint.RuleFixer): TSESLint.RuleFix | null => {
-            const operator = sourceCode.getTokenAfter(
-              node.expression,
-              isNonNullAssertionPunctuator,
-            );
-            if (operator) {
-              return fixer.replaceText(operator, replacement);
-            }
 
-            return null;
-          };
+        // it always exists in non-null assertion
+        const nonNullOperator = sourceCode.getTokenAfter(
+          node.expression,
+          isNonNullAssertionPunctuator,
+        )!;
+
+        function replaceTokenWithOptional(): TSESLint.ReportFixFunction {
+          return fixer => fixer.replaceText(nonNullOperator, '?.');
         }
-        function removeToken(): TSESLint.ReportFixFunction {
-          return (fixer: TSESLint.RuleFixer): TSESLint.RuleFix | null => {
-            const operator = sourceCode.getTokenAfter(
-              node.expression,
-              isNonNullAssertionPunctuator,
-            );
-            if (operator) {
-              return fixer.remove(operator);
-            }
 
-            return null;
-          };
+        function removeToken(): TSESLint.ReportFixFunction {
+          return fixer => fixer.remove(nonNullOperator);
         }
 
         if (
@@ -67,13 +53,21 @@ export default createRule<[], MessageIds>({
               // it is x![y]?.z
               suggest.push({
                 messageId: 'suggestOptionalChain',
-                fix: convertTokenToOptional('?.'),
+                fix: replaceTokenWithOptional(),
               });
             } else {
               // it is x!.y?.z
               suggest.push({
                 messageId: 'suggestOptionalChain',
-                fix: convertTokenToOptional('?'),
+                fix(fixer) {
+                  // x!.y?.z
+                  //   ^ punctuator
+                  const punctuator = sourceCode.getTokenAfter(nonNullOperator)!;
+                  return [
+                    fixer.remove(nonNullOperator),
+                    fixer.insertTextBefore(punctuator, '?'),
+                  ];
+                },
               });
             }
           } else {
@@ -99,7 +93,7 @@ export default createRule<[], MessageIds>({
             // it is x.y?.z!()
             suggest.push({
               messageId: 'suggestOptionalChain',
-              fix: convertTokenToOptional('?.'),
+              fix: replaceTokenWithOptional(),
             });
           } else {
             // it is x.y.z!?.()
diff --git a/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts b/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
index 10dbb0d09c3c..0400ec452e27 100644
--- a/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
+++ b/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
@@ -1,4 +1,4 @@
-import { RuleTester } from '@typescript-eslint/rule-tester';
+import { noFormat, RuleTester } from '@typescript-eslint/rule-tester';
 
 import rule from '../../src/rules/no-non-null-assertion';
 
@@ -293,5 +293,77 @@ ruleTester.run('no-non-null-assertion', rule, {
         },
       ],
     },
+    {
+      code: noFormat`
+x!
+.y
+      `,
+      errors: [
+        {
+          messageId: 'noNonNull',
+          line: 2,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'suggestOptionalChain',
+              output: `
+x
+?.y
+      `,
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: noFormat`
+x!
+// comment
+.y
+      `,
+      errors: [
+        {
+          messageId: 'noNonNull',
+          line: 2,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'suggestOptionalChain',
+              output: `
+x
+// comment
+?.y
+      `,
+            },
+          ],
+        },
+      ],
+    },
+    {
+      code: noFormat`
+x!
+ // comment
+    . /* comment */
+      y
+      `,
+      errors: [
+        {
+          messageId: 'noNonNull',
+          line: 2,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'suggestOptionalChain',
+              output: `
+x
+ // comment
+    ?. /* comment */
+      y
+      `,
+            },
+          ],
+        },
+      ],
+    },
   ],
 });

From d46a14281ac38d3c92f4c55bfd6635ef6ced3f34 Mon Sep 17 00:00:00 2001
From: auvred <aauvred@gmail.com>
Date: Thu, 4 Jan 2024 11:05:06 +0000
Subject: [PATCH 2/2] test: add new case

---
 .../tests/rules/no-non-null-assertion.test.ts | 24 +++++++++++++++++++
 1 file changed, 24 insertions(+)

diff --git a/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts b/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
index 0400ec452e27..d1a93c058d12 100644
--- a/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
+++ b/packages/eslint-plugin/tests/rules/no-non-null-assertion.test.ts
@@ -365,5 +365,29 @@ x
         },
       ],
     },
+    {
+      code: noFormat`
+x!
+ // comment
+     /* comment */ ['y']
+      `,
+      errors: [
+        {
+          messageId: 'noNonNull',
+          line: 2,
+          column: 1,
+          suggestions: [
+            {
+              messageId: 'suggestOptionalChain',
+              output: `
+x?.
+ // comment
+     /* comment */ ['y']
+      `,
+            },
+          ],
+        },
+      ],
+    },
   ],
 });