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             category: "Best Practices",
  18             recommended: false,
  19             url: "https://eslint.org/docs/rules/no-void"
  20         },
  21
  22         messages: {
  23             noVoid: "Expected 'undefined' and instead saw 'void'."
  24         },
  25
  26         schema: [
  27             {
  28                 type: "object",
  29                 properties: {
  30                     allowAsStatement: {
  31                         type: "boolean",
  32                         default: false
  33                     }
  34                 },
  35                 additionalProperties: false
  36             }
  37         ]
  38     },
  39
  40     create(context) {
  41         const allowAsStatement =
  42             context.options[0] && context.options[0].allowAsStatement;
  43
  44         //--------------------------------------------------------------------------
  45         // Public
  46         //--------------------------------------------------------------------------
  47
  48         return {
  49             'UnaryExpression[operator="void"]'(node) {
  50                 if (
  51                     allowAsStatement &&
  52                     node.parent &&
  53                     node.parent.type === "ExpressionStatement"
  54                 ) {
  55                     return;
  56                 }
  57                 context.report({
  58                     node,
  59                     messageId: "noVoid"
  60                 });
  61             }
  62         };
  63     }
  64 };