.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-shadow-restricted-names.js

   1 /**
   2  * @fileoverview Disallow shadowing of NaN, undefined, and Infinity (ES5 section 15.1.1)
   3  * @author Michael Ficarra
   4  */
   5 "use strict";
   6
   7 /**
   8  * Determines if a variable safely shadows undefined.
   9  * This is the case when a variable named `undefined` is never assigned to a value (i.e. it always shares the same value
  10  * as the global).
  11  * @param {eslintScope.Variable} variable The variable to check
  12  * @returns {boolean} true if this variable safely shadows `undefined`
  13  */
  14 function safelyShadowsUndefined(variable) {
  15     return variable.name === "undefined" &&
  16         variable.references.every(ref => !ref.isWrite()) &&
  17         variable.defs.every(def => def.node.type === "VariableDeclarator" && def.node.init === null);
  18 }
  19
  20 //------------------------------------------------------------------------------
  21 // Rule Definition
  22 //------------------------------------------------------------------------------
  23
  24 module.exports = {
  25     meta: {
  26         type: "suggestion",
  27
  28         docs: {
  29             description: "disallow identifiers from shadowing restricted names",
  30             category: "Variables",
  31             recommended: true,
  32             url: "https://eslint.org/docs/rules/no-shadow-restricted-names"
  33         },
  34
  35         schema: [],
  36
  37         messages: {
  38             shadowingRestrictedName: "Shadowing of global property '{{name}}'."
  39         }
  40     },
  41
  42     create(context) {
  43
  44
  45         const RESTRICTED = new Set(["undefined", "NaN", "Infinity", "arguments", "eval"]);
  46
  47         return {
  48             "VariableDeclaration, :function, CatchClause"(node) {
  49                 for (const variable of context.getDeclaredVariables(node)) {
  50                     if (variable.defs.length > 0 && RESTRICTED.has(variable.name) && !safelyShadowsUndefined(variable)) {
  51                         context.report({
  52                             node: variable.defs[0].name,
  53                             messageId: "shadowingRestrictedName",
  54                             data: {
  55                                 name: variable.name
  56                             }
  57                         });
  58                     }
  59                 }
  60             }
  61         };
  62
  63     }
  64 };