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

   1 /**
   2  * @fileoverview Rule to flag assignment of the exception parameter
   3  * @author Stephen Murray <spmurrayzzz>
   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 exceptions in `catch` clauses",
  20             recommended: true,
  21             url: "https://eslint.org/docs/rules/no-ex-assign"
  22         },
  23
  24         schema: [],
  25
  26         messages: {
  27             unexpected: "Do not assign to the exception parameter."
  28         }
  29     },
  30
  31     create(context) {
  32
  33         /**
  34          * Finds and reports references that are non initializer and writable.
  35          * @param {Variable} variable A variable to check.
  36          * @returns {void}
  37          */
  38         function checkVariable(variable) {
  39             astUtils.getModifyingReferences(variable.references).forEach(reference => {
  40                 context.report({ node: reference.identifier, messageId: "unexpected" });
  41             });
  42         }
  43
  44         return {
  45             CatchClause(node) {
  46                 context.getDeclaredVariables(node).forEach(checkVariable);
  47             }
  48         };
  49
  50     }
  51 };