| 12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364 | /** * @fileoverview Disallow shadowing of NaN, undefined, and Infinity (ES5 section 15.1.1) * @author Michael Ficarra */"use strict";/** * Determines if a variable safely shadows undefined. * This is the case when a variable named `undefined` is never assigned to a value (i.e. it always shares the same value * as the global). * @param {eslintScope.Variable} variable The variable to check * @returns {boolean} true if this variable safely shadows `undefined` */function safelyShadowsUndefined(variable) {    return variable.name === "undefined" &&        variable.references.every(ref => !ref.isWrite()) &&        variable.defs.every(def => def.node.type === "VariableDeclarator" && def.node.init === null);}//------------------------------------------------------------------------------// Rule Definition//------------------------------------------------------------------------------/** @type {import('../shared/types').Rule} */module.exports = {    meta: {        type: "suggestion",        docs: {            description: "Disallow identifiers from shadowing restricted names",            recommended: true,            url: "https://eslint.org/docs/rules/no-shadow-restricted-names"        },        schema: [],        messages: {            shadowingRestrictedName: "Shadowing of global property '{{name}}'."        }    },    create(context) {        const RESTRICTED = new Set(["undefined", "NaN", "Infinity", "arguments", "eval"]);        return {            "VariableDeclaration, :function, CatchClause"(node) {                for (const variable of context.getDeclaredVariables(node)) {                    if (variable.defs.length > 0 && RESTRICTED.has(variable.name) && !safelyShadowsUndefined(variable)) {                        context.report({                            node: variable.defs[0].name,                            messageId: "shadowingRestrictedName",                            data: {                                name: variable.name                            }                        });                    }                }            }        };    }};
 |