| /** |
| * @fileoverview Rule to flag duplicate arguments |
| * @author Jamund Ferguson |
| */ |
| |
| "use strict"; |
| |
| //------------------------------------------------------------------------------ |
| // Rule Definition |
| //------------------------------------------------------------------------------ |
| |
| module.exports = { |
| meta: { |
| type: "problem", |
| |
| docs: { |
| description: "disallow duplicate arguments in `function` definitions", |
| category: "Possible Errors", |
| recommended: true, |
| url: "https://eslint.org/docs/rules/no-dupe-args" |
| }, |
| |
| schema: [], |
| |
| messages: { |
| unexpected: "Duplicate param '{{name}}'." |
| } |
| }, |
| |
| create(context) { |
| |
| //-------------------------------------------------------------------------- |
| // 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 = context.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 |
| }; |
| |
| } |
| }; |