no-label-var.js

   1 /**
   2  * @fileoverview Rule to flag labels that are the same as an identifier
   3  * @author Ian Christian Myers
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const astUtils = require("./utils/ast-utils");
  13
  14 //------------------------------------------------------------------------------
  15 // Rule Definition
  16 //------------------------------------------------------------------------------
  17
  18 module.exports = {
  19     meta: {
  20         type: "suggestion",
  21
  22         docs: {
  23             description: "disallow labels that share a name with a variable",
  24             category: "Variables",
  25             recommended: false,
  26             url: "https://eslint.org/docs/rules/no-label-var"
  27         },
  28
  29         schema: []
  30     },
  31
  32     create(context) {
  33
  34         //--------------------------------------------------------------------------
  35         // Helpers
  36         //--------------------------------------------------------------------------
  37
  38         /**
  39          * Check if the identifier is present inside current scope
  40          * @param {Object} scope current scope
  41          * @param {string} name To evaluate
  42          * @returns {boolean} True if its present
  43          * @private
  44          */
  45         function findIdentifier(scope, name) {
  46             return astUtils.getVariableByName(scope, name) !== null;
  47         }
  48
  49         //--------------------------------------------------------------------------
  50         // Public API
  51         //--------------------------------------------------------------------------
  52
  53         return {
  54
  55             LabeledStatement(node) {
  56
  57                 // Fetch the innermost scope.
  58                 const scope = context.getScope();
  59
  60                 /*
  61                  * Recursively find the identifier walking up the scope, starting
  62                  * with the innermost scope.
  63                  */
  64                 if (findIdentifier(scope, node.label.name)) {
  65                     context.report({ node, message: "Found identifier with same name as label." });
  66                 }
  67             }
  68
  69         };
  70
  71     }
  72 };