From 3e991bf8a1434b2890a07fe886a5b9e95909a1b5 Mon Sep 17 00:00:00 2001
From: Imad Elyafi <imad@pinterest.com>
Date: Wed, 21 Dec 2016 14:13:27 -0800
Subject: [PATCH] Autofixer for newline-after-import. Fixes #686

---
 .gitignore                              |  3 +++
 docs/rules/newline-after-import.md      |  1 +
 src/rules/newline-after-import.js       | 18 ++++++++++++------
 tests/src/rules/newline-after-import.js | 15 ++++++++++++++-
 4 files changed, 30 insertions(+), 7 deletions(-)

diff --git a/.gitignore b/.gitignore
index 24ceac8ff2..25ab23821a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -34,3 +34,6 @@ node_modules
 # generated output
 lib/
 **/.nyc_output/
+
+# IDE files
+.idea
diff --git a/docs/rules/newline-after-import.md b/docs/rules/newline-after-import.md
index 0ad2cba015..441fc29d7c 100644
--- a/docs/rules/newline-after-import.md
+++ b/docs/rules/newline-after-import.md
@@ -1,6 +1,7 @@
 # newline-after-import
 
 Enforces having an empty line 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 3198a95792..49dad2b126 100644
--- a/src/rules/newline-after-import.js
+++ b/src/rules/newline-after-import.js
@@ -42,24 +42,29 @@ function isClassWithDecorator(node) {
   return node.type === 'ClassDeclaration' && node.decorators && node.decorators.length
 }
 
+const EXPECTED_LINE_DIFFERENCE = 2;
+
 module.exports = {
   meta: {
     docs: {},
+    fixable: "code",
   },
   create: function (context) {
-    let level = 0
-    const requireCalls = []
+    let level = 0;
+    const requireCalls = [];
 
     function checkForNewLine(node, nextNode, type) {
       if (isClassWithDecorator(nextNode)) {
-        nextNode = nextNode.decorators[0]
+        nextNode = nextNode.decorators[0];
       }
 
-      if (getLineDifference(node, nextNode) < 2) {
-        let column = node.loc.start.column
+      const lineDifference = getLineDifference(node, nextNode);
+
+      if (lineDifference < EXPECTED_LINE_DIFFERENCE) {
+        let column = node.loc.start.column;
 
         if (node.loc.start.line !== node.loc.end.line) {
-          column = 0
+          column = 0;
         }
 
         context.report({
@@ -68,6 +73,7 @@ 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 afd942ef0b..2c41415adc 100644
--- a/tests/src/rules/newline-after-import.js
+++ b/tests/src/rules/newline-after-import.js
@@ -146,6 +146,7 @@ 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,
@@ -155,6 +156,7 @@ 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,
@@ -164,6 +166,7 @@ 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,
@@ -179,6 +182,7 @@ 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,
@@ -194,6 +198,7 @@ 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,
@@ -209,6 +214,7 @@ 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,
@@ -217,6 +223,7 @@ 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,
@@ -225,6 +232,7 @@ 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,
@@ -235,6 +243,7 @@ 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,
@@ -245,6 +254,7 @@ 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,
@@ -254,6 +264,7 @@ 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,
@@ -263,6 +274,7 @@ 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,
@@ -273,6 +285,7 @@ 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,
@@ -282,4 +295,4 @@ ruleTester.run('newline-after-import', require('rules/newline-after-import'), {
       parser: 'babel-eslint',
     },
   ],
-})
+});