feat: update no-lone-blocks for class static blocks (#15295)

Updates the `no-lone-blocks` rule to report lone blocks at the top level of class static blocks. Refs #15016
eslint · Nov 15, 2021 · cdaa541 · cdaa541
1 parent 8611538
commit cdaa541
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diff --git a/docs/rules/no-lone-blocks.md b/docs/rules/no-lone-blocks.md
@@ -42,6 +42,14 @@ function bar() {
     aLabel: {
     }
 }
+
+class C {
+    static {
+        {
+            foo();
+        }
+    }
+}
 ```
 
 Examples of **correct** code for this rule with ES6 environment:
@@ -78,6 +86,18 @@ function bar() {
 
 aLabel: {
 }
+
+class C {
+    static {
+        lbl: {
+            if (something) {
+                break lbl;
+            }
+
+            foo();
+        }
+    }
+}
 ```
 
 Examples of **correct** code for this rule with ES6 environment and strict mode via `"parserOptions": { "sourceType": "module" }` in the ESLint configuration or `"use strict"` directive in the code:

diff --git a/lib/rules/no-lone-blocks.js b/lib/rules/no-lone-blocks.js
@@ -39,7 +39,9 @@ module.exports = {
          * @returns {void}
          */
         function report(node) {
-            const messageId = node.parent.type === "BlockStatement" ? "redundantNestedBlock" : "redundantBlock";
+            const messageId = node.parent.type === "BlockStatement" || node.parent.type === "StaticBlock"
+                ? "redundantNestedBlock"
+                : "redundantBlock";
 
             context.report({
                 node,
@@ -54,6 +56,7 @@ module.exports = {
          */
         function isLoneBlock(node) {
             return node.parent.type === "BlockStatement" ||
+                node.parent.type === "StaticBlock" ||
                 node.parent.type === "Program" ||
 
                 // Don't report blocks in switch cases if the block is the only statement of the case.
@@ -99,7 +102,10 @@ module.exports = {
                         loneBlocks.pop();
                         report(node);
                     } else if (
-                        node.parent.type === "BlockStatement" &&
+                        (
+                            node.parent.type === "BlockStatement" ||
+                            node.parent.type === "StaticBlock"
+                        ) &&
                         node.parent.body.length === 1
                     ) {
                         report(node);

diff --git a/tests/lib/rules/no-lone-blocks.js b/tests/lib/rules/no-lone-blocks.js
@@ -57,7 +57,16 @@ ruleTester.run("no-lone-blocks", rule, {
             }
           }
         `,
-        { code: "function foo() { { const x = 4 } const x = 3 }", parserOptions: { ecmaVersion: 6 } }
+        { code: "function foo() { { const x = 4 } const x = 3 }", parserOptions: { ecmaVersion: 6 } },
+
+        { code: "class C { static {} }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { foo; } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { if (foo) { block; } } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { lbl: { block; } } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { { let block; } something; } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { something; { const block = 1; } } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { { function block(){} } something; } }", parserOptions: { ecmaVersion: 2022 } },
+        { code: "class C { static { something; { class block {}  } } }", parserOptions: { ecmaVersion: 2022 } }
     ],
     invalid: [
         {
@@ -235,6 +244,202 @@ ruleTester.run("no-lone-blocks", rule, {
                 type: "BlockStatement",
                 line: 3
             }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  if (foo) {
+                    {
+                        let block;
+                    }
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 5
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  if (foo) {
+                    {
+                        block;
+                    }
+                    something;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 5
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    block;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    let block;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    const block = 1;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    function block() {}
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    class block {}
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    var block;
+                  }
+                  something;
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  something;
+                  {
+                    var block;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 5
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  {
+                    block;
+                  }
+                  something;
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 4
+            }]
+        },
+        {
+            code: `
+              class C {
+                static {
+                  something;
+                  {
+                    block;
+                  }
+                }
+              }
+            `,
+            parserOptions: { ecmaVersion: 2022 },
+            errors: [{
+                messageId: "redundantNestedBlock",
+                type: "BlockStatement",
+                line: 5
+            }]
         }
     ]
 });