.config/coc/extensions/node_modules/coc-prettier/node_modules/eslint/lib/rules/no-duplicate-case.js

   1 /**
   2  * @fileoverview Rule to disallow a duplicate case label.
   3  * @author Dieter Oberkofler
   4  * @author Burak Yigit Kaya
   5  */
   6
   7 "use strict";
   8
   9 //------------------------------------------------------------------------------
  10 // Rule Definition
  11 //------------------------------------------------------------------------------
  12
  13 module.exports = {
  14     meta: {
  15         type: "problem",
  16
  17         docs: {
  18             description: "disallow duplicate case labels",
  19             category: "Possible Errors",
  20             recommended: true,
  21             url: "https://eslint.org/docs/rules/no-duplicate-case"
  22         },
  23
  24         schema: [],
  25
  26         messages: {
  27             unexpected: "Duplicate case label."
  28         }
  29     },
  30
  31     create(context) {
  32         const sourceCode = context.getSourceCode();
  33
  34         return {
  35             SwitchStatement(node) {
  36                 const previousKeys = new Set();
  37
  38                 for (const switchCase of node.cases) {
  39                     if (switchCase.test) {
  40                         const key = sourceCode.getText(switchCase.test);
  41
  42                         if (previousKeys.has(key)) {
  43                             context.report({ node: switchCase, messageId: "unexpected" });
  44                         } else {
  45                             previousKeys.add(key);
  46                         }
  47                     }
  48                 }
  49             }
  50         };
  51     }
  52 };