| /** |
| * @fileoverview Rule to flag use of an lexical declarations inside a case clause |
| * @author Erik Arvidsson |
| */ |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "suggestion", |
| |
| docs: { |
| description: "disallow lexical declarations in case clauses", |
| category: "Best Practices", |
| recommended: true, |
| url: "https://eslint.org/docs/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" |
| }); |
| } |
| } |
| } |
| }; |
| |
| } |
| }; |