eslint/lib/rules/no-const-assign.js

   1 /**
   2  * @fileoverview A rule to disallow modifying variables that are declared using `const`
   3  * @author Toru Nagashima
   4  */
   5
   6 "use strict";
   7
   8 const astUtils = require("./utils/ast-utils");
   9
  10 //------------------------------------------------------------------------------
  11 // Rule Definition
  12 //------------------------------------------------------------------------------
  13
  14 module.exports = {
  15     meta: {
  16         type: "problem",
  17
  18         docs: {
  19             description: "disallow reassigning `const` variables",
  20             category: "ECMAScript 6",
  21             recommended: true,
  22             url: "https://eslint.org/docs/rules/no-const-assign"
  23         },
  24
  25         schema: [],
  26
  27         messages: {
  28             const: "'{{name}}' is constant."
  29         }
  30     },
  31
  32     create(context) {
  33
  34         /**
  35          * Finds and reports references that are non initializer and writable.
  36          * @param {Variable} variable A variable to check.
  37          * @returns {void}
  38          */
  39         function checkVariable(variable) {
  40             astUtils.getModifyingReferences(variable.references).forEach(reference => {
  41                 context.report({ node: reference.identifier, messageId: "const", data: { name: reference.identifier.name } });
  42             });
  43         }
  44
  45         return {
  46             VariableDeclaration(node) {
  47                 if (node.kind === "const") {
  48                     context.getDeclaredVariables(node).forEach(checkVariable);
  49                 }
  50             }
  51         };
  52
  53     }
  54 };