Update: Change no-duplicate-case to comparing tokens (fixes #13485)

lib/rules/no-duplicate-case.js

@@ -6,6 +6,12 @@
 
 "use strict";
 
+//------------------------------------------------------------------------------
+// Requirements
+//------------------------------------------------------------------------------
+
+const astUtils = require("./utils/ast-utils");
+
 //------------------------------------------------------------------------------
 // Rule Definition
 //------------------------------------------------------------------------------
@@ -31,18 +37,31 @@ module.exports = {
     create(context) {
         const sourceCode = context.getSourceCode();
 
+        /**
+         * Determines whether the two given nodes are considered to be equal.
+         * @param {ASTNode} a First node.
+         * @param {ASTNode} b Second node.
+         * @returns {boolean} `true` if the nodes are considered to be equal.
+         */
+        function equal(a, b) {
+            if (a.type !== b.type) {
+                return false;
+            }
+
+            return astUtils.equalTokens(a, b, sourceCode);
+        }
         return {
             SwitchStatement(node) {
-                const previousKeys = new Set();
+                const previousTests = [];
 
                 for (const switchCase of node.cases) {
                     if (switchCase.test) {
-                        const key = sourceCode.getText(switchCase.test);
+                        const test = switchCase.test;
 
-                        if (previousKeys.has(key)) {
+                        if (previousTests.some(previousTest => equal(previousTest, test))) {
                             context.report({ node: switchCase, messageId: "unexpected" });
                         } else {
-                            previousKeys.add(key);
+                            previousTests.push(test);
                         }
                     }
                 }

tests/lib/rules/no-duplicate-case.js

@@ -128,6 +128,66 @@ ruleTester.run("no-duplicate-case", rule, {
                     column: 74
                 }
             ]
+        },
+        {
+            code: "var a = 1, p = {p: {p1: 1, p2: 1}}; switch (a) {case p.p.p1: break; case p. p // comment\n .p1: break; default: break;}",
+            errors: [{
+                messageId: "unexpected",
+                type: "SwitchCase",
+                column: 69
+            }]
+        },
+        {
+            code: "var a = 1, p = {p: {p1: 1, p2: 1}}; switch (a) {case p .p\n/* comment */\n.p1: break; case p.p.p1: break; default: break;}",
+            errors: [{
+                messageId: "unexpected",
+                type: "SwitchCase",
+                line: 3,
+                column: 13
+            }]
+        },
+        {
+            code: "var a = 1, p = {p: {p1: 1, p2: 1}}; switch (a) {case p .p\n/* comment */\n.p1: break; case p. p // comment\n .p1: break; default: break;}",
+            errors: [{
+                messageId: "unexpected",
+                type: "SwitchCase",
+                line: 3,
+                column: 13
+            }]
+        },
+        {
+            code: "var a = 1, p = {p: {p1: 1, p2: 1}}; switch (a) {case p.p.p1: break; case p. p // comment\n .p1: break; case p .p\n/* comment */\n.p1: break; default: break;}",
+            errors: [
+                {
+                    messageId: "unexpected",
+                    type: "SwitchCase",
+                    line: 1,
+                    column: 69
+                },
+                {
+                    messageId: "unexpected",
+                    type: "SwitchCase",
+                    line: 2,
+                    column: 14
+                }
+            ]
+        },
+        {
+            code: "var a = 1, f = function(s) { return { p1: s } }; switch (a) {case f(a + 1).p1: break; case f(a+1).p1: break; default: break;}",
+            errors: [{
+                messageId: "unexpected",
+                type: "SwitchCase",
+                column: 87
+            }]
+        },
+        {
+            code: "var a = 1, f = function(s) { return { p1: s } }; switch (a) {case f(\na + 1 // comment\n).p1: break; case f(a+1)\n.p1: break; default: break;}",
+            errors: [{
+                messageId: "unexpected",
+                type: "SwitchCase",
+                line: 3,
+                column: 14
+            }]
         }
     ]
 });