.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-lonely-if.js

   1 /**
   2  * @fileoverview Rule to disallow if as the only statement in an else block
   3  * @author Brandon Mills
   4  */
   5 "use strict";
   6
   7 //------------------------------------------------------------------------------
   8 // Rule Definition
   9 //------------------------------------------------------------------------------
  10
  11 module.exports = {
  12     meta: {
  13         type: "suggestion",
  14
  15         docs: {
  16             description: "disallow `if` statements as the only statement in `else` blocks",
  17             category: "Stylistic Issues",
  18             recommended: false,
  19             url: "https://eslint.org/docs/rules/no-lonely-if"
  20         },
  21
  22         schema: [],
  23         fixable: "code",
  24
  25         messages: {
  26             unexpectedLonelyIf: "Unexpected if as the only statement in an else block."
  27         }
  28     },
  29
  30     create(context) {
  31         const sourceCode = context.getSourceCode();
  32
  33         return {
  34             IfStatement(node) {
  35                 const ancestors = context.getAncestors(),
  36                     parent = ancestors.pop(),
  37                     grandparent = ancestors.pop();
  38
  39                 if (parent && parent.type === "BlockStatement" &&
  40                         parent.body.length === 1 && grandparent &&
  41                         grandparent.type === "IfStatement" &&
  42                         parent === grandparent.alternate) {
  43                     context.report({
  44                         node,
  45                         messageId: "unexpectedLonelyIf",
  46                         fix(fixer) {
  47                             const openingElseCurly = sourceCode.getFirstToken(parent);
  48                             const closingElseCurly = sourceCode.getLastToken(parent);
  49                             const elseKeyword = sourceCode.getTokenBefore(openingElseCurly);
  50                             const tokenAfterElseBlock = sourceCode.getTokenAfter(closingElseCurly);
  51                             const lastIfToken = sourceCode.getLastToken(node.consequent);
  52                             const sourceText = sourceCode.getText();
  53
  54                             if (sourceText.slice(openingElseCurly.range[1],
  55                                 node.range[0]).trim() || sourceText.slice(node.range[1], closingElseCurly.range[0]).trim()) {
  56
  57                                 // Don't fix if there are any non-whitespace characters interfering (e.g. comments)
  58                                 return null;
  59                             }
  60
  61                             if (
  62                                 node.consequent.type !== "BlockStatement" && lastIfToken.value !== ";" && tokenAfterElseBlock &&
  63                                 (
  64                                     node.consequent.loc.end.line === tokenAfterElseBlock.loc.start.line ||
  65                                     /^[([/+`-]/u.test(tokenAfterElseBlock.value) ||
  66                                     lastIfToken.value === "++" ||
  67                                     lastIfToken.value === "--"
  68                                 )
  69                             ) {
  70
  71                                 /*
  72                                  * If the `if` statement has no block, and is not followed by a semicolon, make sure that fixing
  73                                  * the issue would not change semantics due to ASI. If this would happen, don't do a fix.
  74                                  */
  75                                 return null;
  76                             }
  77
  78                             return fixer.replaceTextRange(
  79                                 [openingElseCurly.range[0], closingElseCurly.range[1]],
  80                                 (elseKeyword.range[1] === openingElseCurly.range[0] ? " " : "") + sourceCode.getText(node)
  81                             );
  82                         }
  83                     });
  84                 }
  85             }
  86         };
  87
  88     }
  89 };