.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/init-declarations.js

   1 /**
   2  * @fileoverview A rule to control the style of variable initializations.
   3  * @author Colin Ihrig
   4  */
   5
   6 "use strict";
   7
   8 //------------------------------------------------------------------------------
   9 // Helpers
  10 //------------------------------------------------------------------------------
  11
  12 /**
  13  * Checks whether or not a given node is a for loop.
  14  * @param {ASTNode} block A node to check.
  15  * @returns {boolean} `true` when the node is a for loop.
  16  */
  17 function isForLoop(block) {
  18     return block.type === "ForInStatement" ||
  19     block.type === "ForOfStatement" ||
  20     block.type === "ForStatement";
  21 }
  22
  23 /**
  24  * Checks whether or not a given declarator node has its initializer.
  25  * @param {ASTNode} node A declarator node to check.
  26  * @returns {boolean} `true` when the node has its initializer.
  27  */
  28 function isInitialized(node) {
  29     const declaration = node.parent;
  30     const block = declaration.parent;
  31
  32     if (isForLoop(block)) {
  33         if (block.type === "ForStatement") {
  34             return block.init === declaration;
  35         }
  36         return block.left === declaration;
  37     }
  38     return Boolean(node.init);
  39 }
  40
  41 //------------------------------------------------------------------------------
  42 // Rule Definition
  43 //------------------------------------------------------------------------------
  44
  45 module.exports = {
  46     meta: {
  47         type: "suggestion",
  48
  49         docs: {
  50             description: "require or disallow initialization in variable declarations",
  51             category: "Variables",
  52             recommended: false,
  53             url: "https://eslint.org/docs/rules/init-declarations"
  54         },
  55
  56         schema: {
  57             anyOf: [
  58                 {
  59                     type: "array",
  60                     items: [
  61                         {
  62                             enum: ["always"]
  63                         }
  64                     ],
  65                     minItems: 0,
  66                     maxItems: 1
  67                 },
  68                 {
  69                     type: "array",
  70                     items: [
  71                         {
  72                             enum: ["never"]
  73                         },
  74                         {
  75                             type: "object",
  76                             properties: {
  77                                 ignoreForLoopInit: {
  78                                     type: "boolean"
  79                                 }
  80                             },
  81                             additionalProperties: false
  82                         }
  83                     ],
  84                     minItems: 0,
  85                     maxItems: 2
  86                 }
  87             ]
  88         },
  89         messages: {
  90             initialized: "Variable '{{idName}}' should be initialized on declaration.",
  91             notInitialized: "Variable '{{idName}}' should not be initialized on declaration."
  92         }
  93     },
  94
  95     create(context) {
  96
  97         const MODE_ALWAYS = "always",
  98             MODE_NEVER = "never";
  99
 100         const mode = context.options[0] || MODE_ALWAYS;
 101         const params = context.options[1] || {};
 102
 103         //--------------------------------------------------------------------------
 104         // Public API
 105         //--------------------------------------------------------------------------
 106
 107         return {
 108             "VariableDeclaration:exit"(node) {
 109
 110                 const kind = node.kind,
 111                     declarations = node.declarations;
 112
 113                 for (let i = 0; i < declarations.length; ++i) {
 114                     const declaration = declarations[i],
 115                         id = declaration.id,
 116                         initialized = isInitialized(declaration),
 117                         isIgnoredForLoop = params.ignoreForLoopInit && isForLoop(node.parent);
 118                     let messageId = "";
 119
 120                     if (mode === MODE_ALWAYS && !initialized) {
 121                         messageId = "initialized";
 122                     } else if (mode === MODE_NEVER && kind !== "const" && initialized && !isIgnoredForLoop) {
 123                         messageId = "notInitialized";
 124                     }
 125
 126                     if (id.type === "Identifier" && messageId) {
 127                         context.report({
 128                             node: declaration,
 129                             messageId,
 130                             data: {
 131                                 idName: id.name
 132                             }
 133                         });
 134                     }
 135                 }
 136             }
 137         };
 138     }
 139 };