feature: @putout/plugin-conditions: wrap-with-block: add

Author: coderaiser

docs/syntax-errors.md

@@ -273,3 +273,14 @@ a && (b = a);
 ```
 
 </details>
+
+<details><summary>wrap with block</summary>
+
+```diff
+-if (a)
++if (a) {
+    const b = 5;
++}
+```
+
+</details>

packages/plugin-conditions/README.md

@@ -29,6 +29,7 @@ npm i @putout/plugin-conditions -D
 - ✅ [remove-useless-else](#remove-ureless-else);
 - ✅ [remove-zero](#remove-zero);
 - ✅ [simplify](#simplify);
+- ✅ [wrap-with-block](#wrap-with-block);
 
 ## Config
 
@@ -49,7 +50,9 @@ npm i @putout/plugin-conditions -D
         "conditions/remove-zero": "on",
         "conditions/remove-useless-else": "on",
         "conditions/remove-same-values-condition": "on",
-        "conditions/merge-if-statements": "on"
+        "conditions/merge-if-statements": "on",
+        "conditions/simplify": "on",
+        "conditions/wrap-with-block": "on"
     }
 }
 ```
@@ -431,6 +434,28 @@ for (const [i, el] of entries(elements)) {
 }
 ```
 
+## wrap-with-block
+
+> If you use a declaration instead of a statement, it would be a `SyntaxError`. For example, a `let` declaration is not a statement, so you can't use it in its bare form as the body of an if statement.
+>
+> (c) [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements#difference_between_statements_and_declarations)
+
+### ❌ Example of incorrect code
+
+```js
+const a = 5;
+
+if (a) {}
+```
+
+### ✅ Example of correct code
+
+```js
+if (a) {
+    const a = 5;
+}
+```
+
 ### Comparison
 
 Linter | Rule | Fix

packages/plugin-conditions/lib/index.js

@@ -15,6 +15,7 @@ const removeSameValuesCondition = require('./remove-same-values-condition');
 const addReturn = require('./add-return');
 const convertArrowToCondition = require('./convert-arrow-to-condition');
 const reverseCondition = require('./reverse-condition');
+const wrapWithBlock = require('./wrap-with-block');
 
 module.exports.rules = {
     'apply-comparison-order': applyComparisonOrder,
@@ -32,4 +33,5 @@ module.exports.rules = {
     'add-return': addReturn,
     'convert-arrow-to-condition': convertArrowToCondition,
     'reverse-condition': reverseCondition,
+    'wrap-with-block': wrapWithBlock,
 };

packages/plugin-conditions/lib/wrap-with-block/fixture/wrap-with-block-fix.js

@@ -0,0 +1,7 @@
+if (a) {
+    const a = 5;
+}
+
+if (a) {
+    const x = 3;
+}

packages/plugin-conditions/lib/wrap-with-block/fixture/wrap-with-block.js

@@ -0,0 +1,6 @@
+if (a)
+    const a = 5;
+
+if (a) {
+    const x = 3;
+}

packages/plugin-conditions/lib/wrap-with-block/index.js

@@ -0,0 +1,13 @@
+'use strict';
+
+module.exports.report = () => `Lexical declaration cannot appear in single-statement-context`;
+
+module.exports.match = () => ({
+    'const __a = __b': (vars, path) => {
+        return path.parentPath.isIfStatement();
+    },
+});
+
+module.exports.replace = () => ({
+    'const __a = __b': '{const __a = __b}',
+});

packages/plugin-conditions/lib/wrap-with-block/index.spec.js

@@ -0,0 +1,20 @@
+'use strict';
+
+const {createTest} = require('@putout/test');
+const plugin = require('.');
+
+const test = createTest(__dirname, {
+    plugins: [
+        ['wrap-with-block', plugin],
+    ],
+});
+
+test('conditions: wrap-with-block: report', (t) => {
+    t.report('wrap-with-block', `Lexical declaration cannot appear in single-statement-context`);
+    t.end();
+});
+
+test('conditions: wrap-with-block: transform', (t) => {
+    t.transform('wrap-with-block');
+    t.end();
+});

packages/plugin-conditions/test/conditions.js

@@ -83,3 +83,8 @@ test('plugin-conditions: transform: reverse-condition', (t) => {
     t.transform('reverse-condition');
     t.end();
 });
+
+test('plugin-conditions: transform: wrap-with-block', (t) => {
+    t.transform('wrap-with-block');
+    t.end();
+});

packages/plugin-conditions/test/fixture/wrap-with-block-fix.js

@@ -0,0 +1,7 @@
+if (a) {
+    const a = 5;
+}
+
+if (a) {
+    const x = 3;
+}

packages/plugin-conditions/test/fixture/wrap-with-block.js

@@ -0,0 +1,6 @@
+if (a)
+    const a = 5;
+
+if (a) {
+    const x = 3;
+}