| /** | |
|  * @fileoverview Rule to flag use of an lexical declarations inside a case clause | |
|  * @author Erik Arvidsson | |
|  */ | |
| "use strict"; | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
|  | |
| /** @type {import('../shared/types').Rule} */ | |
| module.exports = { | |
|     meta: { | |
|         type: "suggestion", | |
| 
 | |
|         docs: { | |
|             description: "Disallow lexical declarations in case clauses", | |
|             recommended: true, | |
|             url: "https://eslint.org/docs/latest/rules/no-case-declarations" | |
|         }, | |
| 
 | |
|         schema: [], | |
| 
 | |
|         messages: { | |
|             unexpected: "Unexpected lexical declaration in case block." | |
|         } | |
|     }, | |
| 
 | |
|     create(context) { | |
| 
 | |
|         /** | |
|          * Checks whether or not a node is a lexical declaration. | |
|          * @param {ASTNode} node A direct child statement of a switch case. | |
|          * @returns {boolean} Whether or not the node is a lexical declaration. | |
|          */ | |
|         function isLexicalDeclaration(node) { | |
|             switch (node.type) { | |
|                 case "FunctionDeclaration": | |
|                 case "ClassDeclaration": | |
|                     return true; | |
|                 case "VariableDeclaration": | |
|                     return node.kind !== "var"; | |
|                 default: | |
|                     return false; | |
|             } | |
|         } | |
| 
 | |
|         return { | |
|             SwitchCase(node) { | |
|                 for (let i = 0; i < node.consequent.length; i++) { | |
|                     const statement = node.consequent[i]; | |
| 
 | |
|                     if (isLexicalDeclaration(statement)) { | |
|                         context.report({ | |
|                             node: statement, | |
|                             messageId: "unexpected" | |
|                         }); | |
|                     } | |
|                 } | |
|             } | |
|         }; | |
| 
 | |
|     } | |
| };
 |