[eslint config] [base] [deps] update eslint to v4.9

Author: ljharb

packages/eslint-config-airbnb-base/package.json

@@ -5,7 +5,7 @@
   "main": "index.js",
   "scripts": {
     "prelint": "editorconfig-tools check * rules/* test/*",
-    "lint": "eslint .",
+    "lint": "eslint --report-unused-disable-directives .",
     "tests-only": "babel-tape-runner ./test/test-*.js",
     "prepublish": "(in-install || eslint-find-rules --unused) && (not-in-publish || npm test) && safe-publish-latest",
     "pretest": "npm run --silent lint",
@@ -51,15 +51,15 @@
     "babel-preset-airbnb": "^2.4.0",
     "babel-tape-runner": "^2.0.1",
     "editorconfig-tools": "^0.1.1",
-    "eslint": "^4.8.0",
+    "eslint": "^4.9.0",
     "eslint-find-rules": "^3.1.1",
     "eslint-plugin-import": "^2.7.0",
     "in-publish": "^2.0.0",
     "safe-publish-latest": "^1.1.1",
     "tape": "^4.8.0"
   },
   "peerDependencies": {
-    "eslint": "^4.8.0",
+    "eslint": "^4.9.0",
     "eslint-plugin-import": "^2.7.0"
   },
   "engines": {

packages/eslint-config-airbnb-base/rules/best-practices.js

@@ -57,7 +57,9 @@ module.exports = {
     'no-div-regex': 'off',
 
     // disallow else after a return in an if
-    'no-else-return': 'error',
+    // https://eslint.org/docs/rules/no-else-return
+    // TODO: semver-major, set allowElseIf to false
+    'no-else-return': ['error', { allowElseIf: true }],
 
     // disallow empty functions, except for standalone funcs/arrows
     // http://eslint.org/docs/rules/no-empty-function

packages/eslint-config-airbnb-base/rules/style.js

@@ -3,7 +3,7 @@ module.exports = {
     // enforce line breaks after opening and before closing array brackets
     // http://eslint.org/docs/rules/array-bracket-newline
     // TODO: enable? semver-major
-    'array-bracket-newline': ['off', { multiline: true, minItems: 3 }],
+    'array-bracket-newline': ['off', 'consistent'], // object option alternative: { multiline: true, minItems: 3 }
 
     // enforce line breaks between array elements
     // http://eslint.org/docs/rules/array-element-newline
@@ -153,6 +153,11 @@ module.exports = {
     // http://eslint.org/docs/rules/linebreak-style
     'linebreak-style': ['error', 'unix'],
 
+    // require or disallow an empty line between class members
+    // https://eslint.org/docs/rules/lines-between-class-members
+    // TODO: semver-major: enable
+    'lines-between-class-members': ['off', 'always', { exceptAfterSingleLine: false }],
+
     // enforces empty lines around comments
     'lines-around-comment': 'off',
 
@@ -197,6 +202,10 @@ module.exports = {
     // http://eslint.org/docs/rules/max-statements-per-line
     'max-statements-per-line': ['off', { max: 1 }],
 
+    // enforce a particular style for multiline comments
+    // https://eslint.org/docs/rules/multiline-comment-style
+    'multiline-comment-style': ['off', 'starred-block'],
+
     // require multiline ternary
     // http://eslint.org/docs/rules/multiline-ternary
     // TODO: enable?