.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-empty-function.js

   1 /**
   2  * @fileoverview Rule to disallow empty functions.
   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 // Helpers
  16 //------------------------------------------------------------------------------
  17
  18 const ALLOW_OPTIONS = Object.freeze([
  19     "functions",
  20     "arrowFunctions",
  21     "generatorFunctions",
  22     "methods",
  23     "generatorMethods",
  24     "getters",
  25     "setters",
  26     "constructors"
  27 ]);
  28
  29 /**
  30  * Gets the kind of a given function node.
  31  * @param {ASTNode} node A function node to get. This is one of
  32  *      an ArrowFunctionExpression, a FunctionDeclaration, or a
  33  *      FunctionExpression.
  34  * @returns {string} The kind of the function. This is one of "functions",
  35  *      "arrowFunctions", "generatorFunctions", "asyncFunctions", "methods",
  36  *      "generatorMethods", "asyncMethods", "getters", "setters", and
  37  *      "constructors".
  38  */
  39 function getKind(node) {
  40     const parent = node.parent;
  41     let kind = "";
  42
  43     if (node.type === "ArrowFunctionExpression") {
  44         return "arrowFunctions";
  45     }
  46
  47     // Detects main kind.
  48     if (parent.type === "Property") {
  49         if (parent.kind === "get") {
  50             return "getters";
  51         }
  52         if (parent.kind === "set") {
  53             return "setters";
  54         }
  55         kind = parent.method ? "methods" : "functions";
  56
  57     } else if (parent.type === "MethodDefinition") {
  58         if (parent.kind === "get") {
  59             return "getters";
  60         }
  61         if (parent.kind === "set") {
  62             return "setters";
  63         }
  64         if (parent.kind === "constructor") {
  65             return "constructors";
  66         }
  67         kind = "methods";
  68
  69     } else {
  70         kind = "functions";
  71     }
  72
  73     // Detects prefix.
  74     let prefix = "";
  75
  76     if (node.generator) {
  77         prefix = "generator";
  78     } else if (node.async) {
  79         prefix = "async";
  80     } else {
  81         return kind;
  82     }
  83     return prefix + kind[0].toUpperCase() + kind.slice(1);
  84 }
  85
  86 //------------------------------------------------------------------------------
  87 // Rule Definition
  88 //------------------------------------------------------------------------------
  89
  90 module.exports = {
  91     meta: {
  92         type: "suggestion",
  93
  94         docs: {
  95             description: "disallow empty functions",
  96             category: "Best Practices",
  97             recommended: false,
  98             url: "https://eslint.org/docs/rules/no-empty-function"
  99         },
 100
 101         schema: [
 102             {
 103                 type: "object",
 104                 properties: {
 105                     allow: {
 106                         type: "array",
 107                         items: { enum: ALLOW_OPTIONS },
 108                         uniqueItems: true
 109                     }
 110                 },
 111                 additionalProperties: false
 112             }
 113         ],
 114
 115         messages: {
 116             unexpected: "Unexpected empty {{name}}."
 117         }
 118     },
 119
 120     create(context) {
 121         const options = context.options[0] || {};
 122         const allowed = options.allow || [];
 123
 124         const sourceCode = context.getSourceCode();
 125
 126         /**
 127          * Reports a given function node if the node matches the following patterns.
 128          *
 129          * - Not allowed by options.
 130          * - The body is empty.
 131          * - The body doesn't have any comments.
 132          * @param {ASTNode} node A function node to report. This is one of
 133          *      an ArrowFunctionExpression, a FunctionDeclaration, or a
 134          *      FunctionExpression.
 135          * @returns {void}
 136          */
 137         function reportIfEmpty(node) {
 138             const kind = getKind(node);
 139             const name = astUtils.getFunctionNameWithKind(node);
 140             const innerComments = sourceCode.getTokens(node.body, {
 141                 includeComments: true,
 142                 filter: astUtils.isCommentToken
 143             });
 144
 145             if (allowed.indexOf(kind) === -1 &&
 146                 node.body.type === "BlockStatement" &&
 147                 node.body.body.length === 0 &&
 148                 innerComments.length === 0
 149             ) {
 150                 context.report({
 151                     node,
 152                     loc: node.body.loc.start,
 153                     messageId: "unexpected",
 154                     data: { name }
 155                 });
 156             }
 157         }
 158
 159         return {
 160             ArrowFunctionExpression: reportIfEmpty,
 161             FunctionDeclaration: reportIfEmpty,
 162             FunctionExpression: reportIfEmpty
 163         };
 164     }
 165 };