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irreligious/node_modules/eslint/lib/rules/no-dupe-args.js

80 lines
2.3 KiB
JavaScript

/**
* @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
};
}
};