.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/guard-for-in.js

   1 /**
   2  * @fileoverview Rule to flag for-in loops without if statements inside
   3  * @author Nicholas C. Zakas
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Rule Definition
  10 //------------------------------------------------------------------------------
  11
  12 module.exports = {
  13     meta: {
  14         type: "suggestion",
  15
  16         docs: {
  17             description: "require `for-in` loops to include an `if` statement",
  18             category: "Best Practices",
  19             recommended: false,
  20             url: "https://eslint.org/docs/rules/guard-for-in"
  21         },
  22
  23         schema: [],
  24         messages: {
  25             wrap: "The body of a for-in should be wrapped in an if statement to filter unwanted properties from the prototype."
  26         }
  27     },
  28
  29     create(context) {
  30
  31         return {
  32
  33             ForInStatement(node) {
  34                 const body = node.body;
  35
  36                 // empty statement
  37                 if (body.type === "EmptyStatement") {
  38                     return;
  39                 }
  40
  41                 // if statement
  42                 if (body.type === "IfStatement") {
  43                     return;
  44                 }
  45
  46                 // empty block
  47                 if (body.type === "BlockStatement" && body.body.length === 0) {
  48                     return;
  49                 }
  50
  51                 // block with just if statement
  52                 if (body.type === "BlockStatement" && body.body.length === 1 && body.body[0].type === "IfStatement") {
  53                     return;
  54                 }
  55
  56                 // block that starts with if statement
  57                 if (body.type === "BlockStatement" && body.body.length >= 1 && body.body[0].type === "IfStatement") {
  58                     const i = body.body[0];
  59
  60                     // ... whose consequent is a continue
  61                     if (i.consequent.type === "ContinueStatement") {
  62                         return;
  63                     }
  64
  65                     // ... whose consequent is a block that contains only a continue
  66                     if (i.consequent.type === "BlockStatement" && i.consequent.body.length === 1 && i.consequent.body[0].type === "ContinueStatement") {
  67                         return;
  68                     }
  69                 }
  70
  71                 context.report({ node, messageId: "wrap" });
  72             }
  73         };
  74
  75     }
  76 };