| /** | |
|  * @fileoverview Rule to flag duplicate arguments | |
|  * @author Jamund Ferguson | |
|  */ | |
| 
 | |
| "use strict"; | |
| 
 | |
| //------------------------------------------------------------------------------ | |
| // Rule Definition | |
| //------------------------------------------------------------------------------ | |
|  | |
| /** @type {import('../shared/types').Rule} */ | |
| module.exports = { | |
|     meta: { | |
|         type: "problem", | |
| 
 | |
|         docs: { | |
|             description: "Disallow duplicate arguments in `function` definitions", | |
|             recommended: true, | |
|             url: "https://eslint.org/docs/latest/rules/no-dupe-args" | |
|         }, | |
| 
 | |
|         schema: [], | |
| 
 | |
|         messages: { | |
|             unexpected: "Duplicate param '{{name}}'." | |
|         } | |
|     }, | |
| 
 | |
|     create(context) { | |
| 
 | |
|         const sourceCode = context.sourceCode; | |
| 
 | |
|         //-------------------------------------------------------------------------- | |
|         // Helpers | |
|         //-------------------------------------------------------------------------- | |
|  | |
|         /** | |
|          * Checks whether or not a given definition is a parameter's. | |
|          * @param {eslint-scope.DefEntry} def A definition to check. | |
|          * @returns {boolean} `true` if the definition is a parameter's. | |
|          */ | |
|         function isParameter(def) { | |
|             return def.type === "Parameter"; | |
|         } | |
| 
 | |
|         /** | |
|          * Determines if a given node has duplicate parameters. | |
|          * @param {ASTNode} node The node to check. | |
|          * @returns {void} | |
|          * @private | |
|          */ | |
|         function checkParams(node) { | |
|             const variables = sourceCode.getDeclaredVariables(node); | |
| 
 | |
|             for (let i = 0; i < variables.length; ++i) { | |
|                 const variable = variables[i]; | |
| 
 | |
|                 // Checks and reports duplications. | |
|                 const defs = variable.defs.filter(isParameter); | |
| 
 | |
|                 if (defs.length >= 2) { | |
|                     context.report({ | |
|                         node, | |
|                         messageId: "unexpected", | |
|                         data: { name: variable.name } | |
|                     }); | |
|                 } | |
|             } | |
|         } | |
| 
 | |
|         //-------------------------------------------------------------------------- | |
|         // Public API | |
|         //-------------------------------------------------------------------------- | |
|  | |
|         return { | |
|             FunctionDeclaration: checkParams, | |
|             FunctionExpression: checkParams | |
|         }; | |
| 
 | |
|     } | |
| };
 |