eslint/lib/rules/no-useless-catch.js

   1 /**
   2  * @fileoverview Reports useless `catch` clauses that just rethrow their error.
   3  * @author Teddy Katz
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Rule Definition
  10 //------------------------------------------------------------------------------
  11
  12 /** @type {import('../shared/types').Rule} */
  13 module.exports = {
  14     meta: {
  15         type: "suggestion",
  16
  17         docs: {
  18             description: "disallow unnecessary `catch` clauses",
  19             recommended: true,
  20             url: "https://eslint.org/docs/rules/no-useless-catch"
  21         },
  22
  23         schema: [],
  24
  25         messages: {
  26             unnecessaryCatchClause: "Unnecessary catch clause.",
  27             unnecessaryCatch: "Unnecessary try/catch wrapper."
  28         }
  29     },
  30
  31     create(context) {
  32         return {
  33             CatchClause(node) {
  34                 if (
  35                     node.param &&
  36                     node.param.type === "Identifier" &&
  37                     node.body.body.length &&
  38                     node.body.body[0].type === "ThrowStatement" &&
  39                     node.body.body[0].argument.type === "Identifier" &&
  40                     node.body.body[0].argument.name === node.param.name
  41                 ) {
  42                     if (node.parent.finalizer) {
  43                         context.report({
  44                             node,
  45                             messageId: "unnecessaryCatchClause"
  46                         });
  47                     } else {
  48                         context.report({
  49                             node: node.parent,
  50                             messageId: "unnecessaryCatch"
  51                         });
  52                     }
  53                 }
  54             }
  55         };
  56     }
  57 };