.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-extra-label.js

   1 /**
   2  * @fileoverview Rule to disallow unnecessary labels
   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 unnecessary labels",
  24             category: "Best Practices",
  25             recommended: false,
  26             url: "https://eslint.org/docs/rules/no-extra-label"
  27         },
  28
  29         schema: [],
  30         fixable: "code",
  31
  32         messages: {
  33             unexpected: "This label '{{name}}' is unnecessary."
  34         }
  35     },
  36
  37     create(context) {
  38         const sourceCode = context.getSourceCode();
  39         let scopeInfo = null;
  40
  41         /**
  42          * Creates a new scope with a breakable statement.
  43          * @param {ASTNode} node A node to create. This is a BreakableStatement.
  44          * @returns {void}
  45          */
  46         function enterBreakableStatement(node) {
  47             scopeInfo = {
  48                 label: node.parent.type === "LabeledStatement" ? node.parent.label : null,
  49                 breakable: true,
  50                 upper: scopeInfo
  51             };
  52         }
  53
  54         /**
  55          * Removes the top scope of the stack.
  56          * @returns {void}
  57          */
  58         function exitBreakableStatement() {
  59             scopeInfo = scopeInfo.upper;
  60         }
  61
  62         /**
  63          * Creates a new scope with a labeled statement.
  64          *
  65          * This ignores it if the body is a breakable statement.
  66          * In this case it's handled in the `enterBreakableStatement` function.
  67          * @param {ASTNode} node A node to create. This is a LabeledStatement.
  68          * @returns {void}
  69          */
  70         function enterLabeledStatement(node) {
  71             if (!astUtils.isBreakableStatement(node.body)) {
  72                 scopeInfo = {
  73                     label: node.label,
  74                     breakable: false,
  75                     upper: scopeInfo
  76                 };
  77             }
  78         }
  79
  80         /**
  81          * Removes the top scope of the stack.
  82          *
  83          * This ignores it if the body is a breakable statement.
  84          * In this case it's handled in the `exitBreakableStatement` function.
  85          * @param {ASTNode} node A node. This is a LabeledStatement.
  86          * @returns {void}
  87          */
  88         function exitLabeledStatement(node) {
  89             if (!astUtils.isBreakableStatement(node.body)) {
  90                 scopeInfo = scopeInfo.upper;
  91             }
  92         }
  93
  94         /**
  95          * Reports a given control node if it's unnecessary.
  96          * @param {ASTNode} node A node. This is a BreakStatement or a
  97          *      ContinueStatement.
  98          * @returns {void}
  99          */
 100         function reportIfUnnecessary(node) {
 101             if (!node.label) {
 102                 return;
 103             }
 104
 105             const labelNode = node.label;
 106
 107             for (let info = scopeInfo; info !== null; info = info.upper) {
 108                 if (info.breakable || info.label && info.label.name === labelNode.name) {
 109                     if (info.breakable && info.label && info.label.name === labelNode.name) {
 110                         context.report({
 111                             node: labelNode,
 112                             messageId: "unexpected",
 113                             data: labelNode,
 114                             fix(fixer) {
 115                                 const breakOrContinueToken = sourceCode.getFirstToken(node);
 116
 117                                 if (sourceCode.commentsExistBetween(breakOrContinueToken, labelNode)) {
 118                                     return null;
 119                                 }
 120
 121                                 return fixer.removeRange([breakOrContinueToken.range[1], labelNode.range[1]]);
 122                             }
 123                         });
 124                     }
 125                     return;
 126                 }
 127             }
 128         }
 129
 130         return {
 131             WhileStatement: enterBreakableStatement,
 132             "WhileStatement:exit": exitBreakableStatement,
 133             DoWhileStatement: enterBreakableStatement,
 134             "DoWhileStatement:exit": exitBreakableStatement,
 135             ForStatement: enterBreakableStatement,
 136             "ForStatement:exit": exitBreakableStatement,
 137             ForInStatement: enterBreakableStatement,
 138             "ForInStatement:exit": exitBreakableStatement,
 139             ForOfStatement: enterBreakableStatement,
 140             "ForOfStatement:exit": exitBreakableStatement,
 141             SwitchStatement: enterBreakableStatement,
 142             "SwitchStatement:exit": exitBreakableStatement,
 143             LabeledStatement: enterLabeledStatement,
 144             "LabeledStatement:exit": exitLabeledStatement,
 145             BreakStatement: reportIfUnnecessary,
 146             ContinueStatement: reportIfUnnecessary
 147         };
 148     }
 149 };