fix: enforceLineBreak now handles export type correctly (#488)

* fix enforce breakline with export type

* add case for exports with comments

* switch to using comments before func

Author: Brian Chen

src/rules/enforceLineBreak.js

@@ -12,24 +12,31 @@ const create = (context) => {
         return;
       }
 
+      const exportedType = node.parent.type === 'ExportNamedDeclaration';
+      const leadingComments = sourceCode.getCommentsBefore(exportedType ? node.parent : node);
+      const hasLeadingComments = leadingComments.length > 0;
+
       if (node.loc.start.line !== 1) {
-        if (node.leadingComments && node.leadingComments[0].loc.start.line !== 1) {
-          const lineAboveComment = sourceCode.lines[node.leadingComments[0].loc.start.line - 2];
+        if (hasLeadingComments && leadingComments[0].loc.start.line !== 1) {
+          const lineAboveComment = sourceCode.lines[leadingComments[0].loc.start.line - 2];
           if (lineAboveComment !== '') {
             context.report({
               fix (fixer) {
-                return fixer.insertTextBeforeRange(node.leadingComments[0].range, '\n');
+                return fixer.insertTextBeforeRange(leadingComments[0].range, '\n');
               },
               message: breakLineMessage('above'),
               node,
             });
           }
-        } else if (!node.leadingComments) {
+        } else if (!hasLeadingComments) {
           const isLineAbove = sourceCode.lines[node.loc.start.line - 2];
           if (isLineAbove !== '') {
             context.report({
               fix (fixer) {
-                return fixer.insertTextBefore(node, '\n');
+                return fixer.insertTextBefore(
+                  exportedType ? node.parent : node,
+                  '\n',
+                );
               },
               message: breakLineMessage('above'),
               node,

tests/rules/assertions/enforceLineBreak.js

@@ -36,6 +36,36 @@ export default {
       ],
       output: 'type hello = 34;\n\nconst som = "jes";\n\ntype fed = "hed";\n',
     },
+    {
+      code: 'const a = 5;\nexport type hello = 34;\n',
+      errors: [
+        {message: 'New line required above type declaration'},
+      ],
+      output: 'const a = 5;\n\nexport type hello = 34;\n',
+    },
+    {
+      code: 'const a = 5;\n// a comment\nexport type hello = 34;\n',
+      errors: [
+        {message: 'New line required above type declaration'},
+      ],
+      output: 'const a = 5;\n\n// a comment\nexport type hello = 34;\n',
+    },
+    {
+      code: `const a = 5;
+/**
+ * a jsdoc block
+ */
+type hello = 34;`,
+      errors: [
+        {message: 'New line required above type declaration'},
+      ],
+      output: `const a = 5;
+
+/**
+ * a jsdoc block
+ */
+type hello = 34;`,
+    },
   ],
   valid: [
     {
@@ -77,5 +107,8 @@ type Props = {
 
 type RoadT = "grass" | "gravel" | "cement";`,
     },
+    {
+      code: '// @flow\ntype A = string',
+    },
   ],
 };