.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-invalid-this.js

   1 /**
   2  * @fileoverview A rule to disallow `this` keywords outside of classes or class-like objects.
   3  * @author Toru Nagashima
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Requirements
  10 //------------------------------------------------------------------------------
  11
  12 const astUtils = require("./utils/ast-utils");
  13
  14 //------------------------------------------------------------------------------
  15 // Rule Definition
  16 //------------------------------------------------------------------------------
  17
  18 module.exports = {
  19     meta: {
  20         type: "suggestion",
  21
  22         docs: {
  23             description: "disallow `this` keywords outside of classes or class-like objects",
  24             category: "Best Practices",
  25             recommended: false,
  26             url: "https://eslint.org/docs/rules/no-invalid-this"
  27         },
  28
  29         schema: [
  30             {
  31                 type: "object",
  32                 properties: {
  33                     capIsConstructor: {
  34                         type: "boolean",
  35                         default: true
  36                     }
  37                 },
  38                 additionalProperties: false
  39             }
  40         ],
  41
  42         messages: {
  43             unexpectedThis: "Unexpected 'this'."
  44         }
  45     },
  46
  47     create(context) {
  48         const options = context.options[0] || {};
  49         const capIsConstructor = options.capIsConstructor !== false;
  50         const stack = [],
  51             sourceCode = context.getSourceCode();
  52
  53         /**
  54          * Gets the current checking context.
  55          *
  56          * The return value has a flag that whether or not `this` keyword is valid.
  57          * The flag is initialized when got at the first time.
  58          * @returns {{valid: boolean}}
  59          *   an object which has a flag that whether or not `this` keyword is valid.
  60          */
  61         stack.getCurrent = function() {
  62             const current = this[this.length - 1];
  63
  64             if (!current.init) {
  65                 current.init = true;
  66                 current.valid = !astUtils.isDefaultThisBinding(
  67                     current.node,
  68                     sourceCode,
  69                     { capIsConstructor }
  70                 );
  71             }
  72             return current;
  73         };
  74
  75         /**
  76          * Pushs new checking context into the stack.
  77          *
  78          * The checking context is not initialized yet.
  79          * Because most functions don't have `this` keyword.
  80          * When `this` keyword was found, the checking context is initialized.
  81          * @param {ASTNode} node A function node that was entered.
  82          * @returns {void}
  83          */
  84         function enterFunction(node) {
  85
  86             // `this` can be invalid only under strict mode.
  87             stack.push({
  88                 init: !context.getScope().isStrict,
  89                 node,
  90                 valid: true
  91             });
  92         }
  93
  94         /**
  95          * Pops the current checking context from the stack.
  96          * @returns {void}
  97          */
  98         function exitFunction() {
  99             stack.pop();
 100         }
 101
 102         return {
 103
 104             /*
 105              * `this` is invalid only under strict mode.
 106              * Modules is always strict mode.
 107              */
 108             Program(node) {
 109                 const scope = context.getScope(),
 110                     features = context.parserOptions.ecmaFeatures || {};
 111
 112                 stack.push({
 113                     init: true,
 114                     node,
 115                     valid: !(
 116                         scope.isStrict ||
 117                         node.sourceType === "module" ||
 118                         (features.globalReturn && scope.childScopes[0].isStrict)
 119                     )
 120                 });
 121             },
 122
 123             "Program:exit"() {
 124                 stack.pop();
 125             },
 126
 127             FunctionDeclaration: enterFunction,
 128             "FunctionDeclaration:exit": exitFunction,
 129             FunctionExpression: enterFunction,
 130             "FunctionExpression:exit": exitFunction,
 131
 132             // Reports if `this` of the current context is invalid.
 133             ThisExpression(node) {
 134                 const current = stack.getCurrent();
 135
 136                 if (current && !current.valid) {
 137                     context.report({
 138                         node,
 139                         messageId: "unexpectedThis"
 140                     });
 141                 }
 142             }
 143         };
 144     }
 145 };