Add suggestion for 'no-same-line-conditional' (#339)

README.md

@@ -37,7 +37,7 @@ Code Smells, or maintainability issues, are raised for places of code which migh
 * Template literals should not be nested ([`no-nested-template-literals`])
 * Boolean literals should not be redundant ([`no-redundant-boolean`])
 * Jump statements should not be redundant ([`no-redundant-jump`]) (:wrench: *fixable*)
-* Conditionals should start on new lines ([`no-same-line-conditional`])
+* Conditionals should start on new lines ([`no-same-line-conditional`]) (:wrench: *fixable*)
 * "switch" statements should have at least 3 "case" clauses ([`no-small-switch`])
 * Collection and array contents should be used ([`no-unused-collection`])
 * "catch" clauses should do more than rethrow ([`no-useless-catch`])

docs/rules/no-same-line-conditional.md

@@ -1,5 +1,7 @@
 # no-same-line-conditional
 
+:wrench: *fixable*
+
 Code is clearest when each statement has its own line. Nonetheless, it is a common pattern to combine on the same line an `if` and its resulting *then* statement. However, when an `if` is placed on the same line as the closing `}` from a preceding *then*, *else* or *else if* part, it is either an error - `else` is missing - or the invitation to a future error as maintainers fail to understand that the two statements are unconnected.
 
 ## Noncompliant Code Example

src/rules/no-same-line-conditional.ts

@@ -35,8 +35,11 @@ const rule: TSESLint.RuleModule<string, string[]> = {
     messages: {
       sameLineCondition: message,
       sonarRuntime: '{{sonarRuntimeData}}',
+      suggestAddingElse: 'Add "else" keyword',
+      suggestAddingNewline: 'Move this "if" to a new line',
     },
     type: 'problem',
+    hasSuggestions: true,
     docs: {
       description: 'Conditionals should start on new lines',
       recommended: 'error',
@@ -70,6 +73,20 @@ const rule: TSESLint.RuleModule<string, string[]> = {
             {
               messageId: 'sameLineCondition',
               loc: followingIfToken.loc,
+              suggest: [
+                {
+                  messageId: 'suggestAddingElse',
+                  fix: fixer => fixer.insertTextBefore(followingIfToken, 'else '),
+                },
+                {
+                  messageId: 'suggestAddingNewline',
+                  fix: fixer =>
+                    fixer.insertTextBefore(
+                      followingIf,
+                      '\n' + ' '.repeat(precedingIf.loc.start.column),
+                    ),
+                },
+              ],
             },
             [issueLocation(precedingIfLastToken.loc)],
             message,

tests/rules/no-same-line-conditional.test.ts

@@ -100,6 +100,23 @@ ruleTester.run('Conditionals should start on new lines', rule, {
           endLine: 3,
           column: 9,
           endColumn: 11,
+          suggestions: [
+            {
+              messageId: 'suggestAddingElse',
+              output: `
+      if (cond1) {
+      } else if (cond2) {
+      }`,
+            },
+            {
+              messageId: 'suggestAddingNewline',
+              output: `
+      if (cond1) {
+      } 
+      if (cond2) {
+      }`,
+            },
+          ],
         },
       ],
     },
@@ -250,5 +267,54 @@ ruleTester.run('Conditionals should start on new lines', rule, {
         },
       ],
     },
+    {
+      code: `
+      function myFunc() {
+        foo(); if (cond1) {
+        } if (cond2) {
+        }
+      }`,
+      options: ['sonar-runtime'],
+      errors: [
+        {
+          messageId: 'sonarRuntime',
+          data: {
+            sonarRuntimeData: JSON.stringify({
+              secondaryLocations: [
+                {
+                  line: 4,
+                  column: 8,
+                  endLine: 4,
+                  endColumn: 9,
+                  message: '',
+                },
+              ],
+              message: 'Move this "if" to a new line or add the missing "else".',
+            }),
+          },
+          suggestions: [
+            {
+              messageId: 'suggestAddingElse',
+              output: `
+      function myFunc() {
+        foo(); if (cond1) {
+        } else if (cond2) {
+        }
+      }`,
+            },
+            {
+              messageId: 'suggestAddingNewline',
+              output: `
+      function myFunc() {
+        foo(); if (cond1) {
+        } 
+               if (cond2) {
+        }
+      }`,
+            },
+          ],
+        },
+      ],
+    },
   ],
 });