From bfdf77a7e22cb9df80fcf9f8e38ce87fc5935526 Mon Sep 17 00:00:00 2001
From: Imad Elyafi <imad@pinterest.com>
Date: Wed, 21 Dec 2016 14:13:27 -0800
Subject: [PATCH] [New] Autofixer for newline-after-import

Fixes #686
---
 docs/rules/newline-after-import.md      |  1 +
 src/rules/newline-after-import.js       | 10 ++++++++-
 tests/src/rules/newline-after-import.js | 27 ++++++++++++++++++++++++-
 3 files changed, 36 insertions(+), 2 deletions(-)

diff --git a/docs/rules/newline-after-import.md b/docs/rules/newline-after-import.md
index a50a1e333..8c5d5760f 100644
--- a/docs/rules/newline-after-import.md
+++ b/docs/rules/newline-after-import.md
@@ -1,6 +1,7 @@
 # newline-after-import
 
 Enforces having one or more empty lines after the last top-level import statement or require call.
++(fixable) The `--fix` option on the [command line] automatically fixes problems reported by this rule.
 
 ## Rule Details
 
diff --git a/src/rules/newline-after-import.js b/src/rules/newline-after-import.js
index 868904ba3..579fe43ac 100644
--- a/src/rules/newline-after-import.js
+++ b/src/rules/newline-after-import.js
@@ -57,6 +57,7 @@ module.exports = {
         'additionalProperties': false,
       },
     ],
+    fixable: 'whitespace',
   },
   create: function (context) {
     let level = 0
@@ -68,7 +69,10 @@ module.exports = {
       }
 
       const options = context.options[0] || { count: 1 }
-      if (getLineDifference(node, nextNode) < options.count + 1) {
+      const lineDifference = getLineDifference(node, nextNode)
+      const EXPECTED_LINE_DIFFERENCE = options.count + 1
+
+      if (lineDifference < EXPECTED_LINE_DIFFERENCE) {
         let column = node.loc.start.column
 
         if (node.loc.start.line !== node.loc.end.line) {
@@ -81,6 +85,10 @@ module.exports = {
             column,
           },
           message: `Expected empty line after ${type} statement not followed by another ${type}.`,
+          fix: fixer => fixer.insertTextAfter(
+            node,
+            '\n'.repeat(EXPECTED_LINE_DIFFERENCE - lineDifference)
+          ),
         })
       }
     }
diff --git a/tests/src/rules/newline-after-import.js b/tests/src/rules/newline-after-import.js
index 0d3120d61..aab38b21b 100644
--- a/tests/src/rules/newline-after-import.js
+++ b/tests/src/rules/newline-after-import.js
@@ -166,6 +166,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
   invalid: [
     {
       code: `import foo from 'foo';\nexport default function() {};`,
+      output: `import foo from 'foo';\n\nexport default function() {};`,
       errors: [ {
         line: 1,
         column: 1,
@@ -175,6 +176,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import foo from 'foo';\n\nexport default function() {};`,
+      output: `import foo from 'foo';\n\n\nexport default function() {};`,
       options: [{ 'count': 2 }],
       errors: [ {
         line: 1,
@@ -183,8 +185,19 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
       } ],
       parserOptions: { sourceType: 'module' },
     },
+    {
+      code: `var foo = require('foo-module');\nvar something = 123;`,
+      output: `var foo = require('foo-module');\n\nvar something = 123;`,
+      errors: [ {
+        line: 1,
+        column: 1,
+        message: REQUIRE_ERROR_MESSAGE,
+      } ],
+      parserOptions: { sourceType: 'module' },
+    },
     {
       code: `import foo from 'foo';\nexport default function() {};`,
+      output: `import foo from 'foo';\n\nexport default function() {};`,
       options: [{ 'count': 1 }],
       errors: [ {
         line: 1,
@@ -195,6 +208,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var foo = require('foo-module');\nvar something = 123;`,
+      output: `var foo = require('foo-module');\n\nvar something = 123;`,
       errors: [ {
         line: 1,
         column: 1,
@@ -204,6 +218,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import foo from 'foo';\nvar a = 123;\n\nimport { bar } from './bar-lib';\nvar b=456;`,
+      output: `import foo from 'foo';\n\nvar a = 123;\n\nimport { bar } from './bar-lib';\n\nvar b=456;`,
       errors: [
       {
         line: 1,
@@ -219,6 +234,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var foo = require('foo-module');\nvar a = 123;\n\nvar bar = require('bar-lib');\nvar b=456;`,
+      output: `var foo = require('foo-module');\n\nvar a = 123;\n\nvar bar = require('bar-lib');\n\nvar b=456;`,
       errors: [
         {
           line: 1,
@@ -234,6 +250,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var foo = require('foo-module');\nvar a = 123;\n\nrequire('bar-lib');\nvar b=456;`,
+      output: `var foo = require('foo-module');\n\nvar a = 123;\n\nrequire('bar-lib');\n\nvar b=456;`,
       errors: [
         {
           line: 1,
@@ -249,6 +266,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var path = require('path');\nvar foo = require('foo');\nvar bar = 42;`,
+      output: `var path = require('path');\nvar foo = require('foo');\n\nvar bar = 42;`,
       errors: [ {
         line: 2,
         column: 1,
@@ -257,6 +275,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var assign = Object.assign || require('object-assign');\nvar foo = require('foo');\nvar bar = 42;`,
+      output: `var assign = Object.assign || require('object-assign');\nvar foo = require('foo');\n\nvar bar = 42;`,
       errors: [ {
         line: 2,
         column: 1,
@@ -265,6 +284,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `require('a');\nfoo(require('b'), require('c'), require('d'));\nrequire('d');\nvar foo = 'bar';`,
+      output: `require('a');\nfoo(require('b'), require('c'), require('d'));\nrequire('d');\n\nvar foo = 'bar';`,
       errors: [
         {
           line: 3,
@@ -275,6 +295,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `require('a');\nfoo(\nrequire('b'),\nrequire('c'),\nrequire('d')\n);\nvar foo = 'bar';`,
+      output: `require('a');\nfoo(\nrequire('b'),\nrequire('c'),\nrequire('d')\n);\n\nvar foo = 'bar';`,
       errors: [
         {
           line: 6,
@@ -285,6 +306,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import path from 'path';\nimport foo from 'foo';\nvar bar = 42;`,
+      output: `import path from 'path';\nimport foo from 'foo';\n\nvar bar = 42;`,
       errors: [ {
         line: 2,
         column: 1,
@@ -294,6 +316,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import path from 'path';import foo from 'foo';var bar = 42;`,
+      output: `import path from 'path';import foo from 'foo';\n\nvar bar = 42;`,
       errors: [ {
         line: 1,
         column: 25,
@@ -303,6 +326,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `import foo from 'foo';\n@SomeDecorator(foo)\nclass Foo {}`,
+      output: `import foo from 'foo';\n\n@SomeDecorator(foo)\nclass Foo {}`,
       errors: [ {
         line: 1,
         column: 1,
@@ -313,6 +337,7 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
     },
     {
       code: `var foo = require('foo');\n@SomeDecorator(foo)\nclass Foo {}`,
+      output: `var foo = require('foo');\n\n@SomeDecorator(foo)\nclass Foo {}`,
       errors: [ {
         line: 1,
         column: 1,
@@ -322,4 +347,4 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
       parser: 'babel-eslint',
     },
   ],
-})
+});