New: add allowSingleLineBlocks opt. to padded-blocks rule (fixes #7145)

docs/rules/padded-blocks.md

@@ -20,7 +20,10 @@ This rule enforces consistent empty line padding within blocks.
 
 ## Options
 
-This rule has one option, which can be a string option or an object option.
+This rule has two options, the first one can be a string option or an object option.
+The second one is an object option, it can allow exceptions.
+
+### First option
 
 String option:
 
@@ -33,6 +36,10 @@ Object option:
 * `"classes"` require or disallow padding within classes
 * `"switches"` require or disallow padding within `switch` statements
 
+### Second option
+
+* `"allowSingleLineBlocks": true` allows single-line blocks
+
 ### always
 
 Examples of **incorrect** code for this rule with the default `"always"` option:
@@ -346,6 +353,42 @@ if (a) {
 }
 ```
 
+### always + allowSingleLineBlocks
+
+Examples of **incorrect** code for this rule with the `"always", {"allowSingleLineBlocks": true}` options:
+
+```js
+/*eslint padded-blocks: ["error", "always", { allowSingleLineBlocks: true }]*/
+
+if (a) {
+    b();
+}
+
+if (a) {
+
+    b();
+}
+
+if (a) {
+    b();
+
+}
+```
+
+Examples of **correct** code for this rule with the `"always", {"allowSingleLineBlocks": true}` options:
+
+```js
+/*eslint padded-blocks: ["error", "always", { allowSingleLineBlocks: true }]*/
+
+if (a) { b(); }
+
+if (a) {
+
+    b();
+
+}
+```
+
 ## When Not To Use It
 
 You can turn this rule off if you are not concerned with the consistency of padding within blocks.

lib/rules/padded-blocks.js

@@ -5,6 +5,12 @@
 
 "use strict";
 
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("../util/ast-utils");
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -45,32 +51,45 @@ module.exports = {
                         minProperties: 1
                     }
                 ]
+            },
+            {
+                type: "object",
+                properties: {
+                    allowSingleLineBlocks: {
+                        type: "boolean"
+                    }
+                }
             }
         ]
     },
 
     create(context) {
         const options = {};
-        const config = context.options[0] || "always";
+        const typeOptions = context.options[0] || "always";
+        const exceptOptions = context.options[1] || {};
 
-        if (typeof config === "string") {
-            const shouldHavePadding = config === "always";
+        if (typeof typeOptions === "string") {
+            const shouldHavePadding = typeOptions === "always";
 
             options.blocks = shouldHavePadding;
             options.switches = shouldHavePadding;
             options.classes = shouldHavePadding;
         } else {
-            if (Object.prototype.hasOwnProperty.call(config, "blocks")) {
-                options.blocks = config.blocks === "always";
+            if (Object.prototype.hasOwnProperty.call(typeOptions, "blocks")) {
+                options.blocks = typeOptions.blocks === "always";
             }
-            if (Object.prototype.hasOwnProperty.call(config, "switches")) {
-                options.switches = config.switches === "always";
+            if (Object.prototype.hasOwnProperty.call(typeOptions, "switches")) {
+                options.switches = typeOptions.switches === "always";
             }
-            if (Object.prototype.hasOwnProperty.call(config, "classes")) {
-                options.classes = config.classes === "always";
+            if (Object.prototype.hasOwnProperty.call(typeOptions, "classes")) {
+                options.classes = typeOptions.classes === "always";
             }
         }
 
+        if (Object.prototype.hasOwnProperty.call(exceptOptions, "allowSingleLineBlocks")) {
+            options.allowSingleLineBlocks = exceptOptions.allowSingleLineBlocks === true;
+        }
+
         const ALWAYS_MESSAGE = "Block must be padded by blank lines.",
             NEVER_MESSAGE = "Block must not be padded by blank lines.";
 
@@ -177,6 +196,10 @@ module.exports = {
                 blockHasTopPadding = isPaddingBetweenTokens(tokenBeforeFirst, firstBlockToken),
                 blockHasBottomPadding = isPaddingBetweenTokens(lastBlockToken, tokenAfterLast);
 
+            if (options.allowSingleLineBlocks && astUtils.isTokenOnSameLine(tokenBeforeFirst, tokenAfterLast)) {
+                return;
+            }
+
             if (requirePaddingFor(node)) {
                 if (!blockHasTopPadding) {
                     context.report({

tests/lib/rules/padded-blocks.js

@@ -54,6 +54,8 @@ ruleTester.run("padded-blocks", rule, {
         { code: "{\na();}", options: ["never"] },
         { code: "{a();\n}", options: ["never"] },
         { code: "{a();}", options: ["never"] },
+        { code: "{a();}", options: ["always", { allowSingleLineBlocks: true }] },
+        { code: "{\n\na();\n\n}", options: ["always", { allowSingleLineBlocks: true }] },
         { code: "{//comment\na();}", options: ["never"] },
         { code: "{\n//comment\na()\n}", options: ["never"] },
         { code: "{a();//comment\n}", options: ["never"] },