eslint/lib/rules/no-void.js

   1 /**
   2  * @fileoverview Rule to disallow use of void operator.
   3  * @author Mike Sidorov
   4  */
   5 "use strict";
   6
   7 //------------------------------------------------------------------------------
   8 // Rule Definition
   9 //------------------------------------------------------------------------------
  10
  11 module.exports = {
  12     meta: {
  13         type: "suggestion",
  14
  15         docs: {
  16             description: "disallow `void` operators",
  17             recommended: false,
  18             url: "https://eslint.org/docs/rules/no-void"
  19         },
  20
  21         messages: {
  22             noVoid: "Expected 'undefined' and instead saw 'void'."
  23         },
  24
  25         schema: [
  26             {
  27                 type: "object",
  28                 properties: {
  29                     allowAsStatement: {
  30                         type: "boolean",
  31                         default: false
  32                     }
  33                 },
  34                 additionalProperties: false
  35             }
  36         ]
  37     },
  38
  39     create(context) {
  40         const allowAsStatement =
  41             context.options[0] && context.options[0].allowAsStatement;
  42
  43         //--------------------------------------------------------------------------
  44         // Public
  45         //--------------------------------------------------------------------------
  46
  47         return {
  48             'UnaryExpression[operator="void"]'(node) {
  49                 if (
  50                     allowAsStatement &&
  51                     node.parent &&
  52                     node.parent.type === "ExpressionStatement"
  53                 ) {
  54                     return;
  55                 }
  56                 context.report({
  57                     node,
  58                     messageId: "noVoid"
  59                 });
  60             }
  61         };
  62     }
  63 };