Merge and deduplicate rule notices

src/rules/convertRules.test.ts

@@ -95,6 +95,7 @@ describe("convertRules", () => {
                     {
                         ruleName: "eslint-rule-a",
                         ruleSeverity: "error",
+                        notices: [],
                     },
                 ],
             ]),
@@ -183,6 +184,51 @@ describe("convertRules", () => {
         );
     });
 
+    it("merges and deduplicates rule notices", () => {
+        // Arrange
+        const tslintRule: TSLintRuleOptions = {
+            ruleArguments: [],
+            ruleName: "tslint-rule-a",
+            ruleSeverity: "error",
+        };
+        const conversionResult = {
+            rules: [
+                {
+                    ruleName: "eslint-rule-a",
+                    notices: ["notice-1", "notice-2"],
+                },
+                {
+                    ruleName: "eslint-rule-a",
+                    notices: ["notice-1"],
+                },
+            ],
+        };
+        const mergedArguments = [{ merged: true }];
+        const converters = new Map([[tslintRule.ruleName, () => conversionResult]]);
+        const mergers = new Map([[conversionResult.rules[0].ruleName, () => mergedArguments]]);
+
+        // Act
+        const { converted } = convertRules(
+            { converters, mergers },
+            { [tslintRule.ruleName]: tslintRule },
+        );
+
+        // Assert
+        expect(converted).toEqual(
+            new Map([
+                [
+                    "eslint-rule-a",
+                    {
+                        ruleArguments: mergedArguments,
+                        ruleName: "eslint-rule-a",
+                        ruleSeverity: "error",
+                        notices: ["notice-1", "notice-2"],
+                    },
+                ],
+            ]),
+        );
+    });
+
     it("marks a new plugin when a conversion has a new plugin", () => {
         // Arrange
         const tslintRule: TSLintRuleOptions = {

src/rules/convertRules.ts

@@ -48,14 +48,18 @@ export const convertRules = (
 
         for (const changes of conversion.rules) {
             const existingConversion = converted.get(changes.ruleName);
+
             const newConversion = {
                 ...changes,
+                notices: changes.notices || [],
                 ruleSeverity: convertTSLintRuleSeverity(tslintRule.ruleSeverity),
             };
 
             if (existingConversion === undefined) {
                 converted.set(changes.ruleName, newConversion);
                 continue;
+            } else {
+                existingConversion.notices = existingConversion.notices || [];
             }
 
             const merger = dependencies.mergers.get(changes.ruleName);
@@ -69,16 +73,15 @@ export const convertRules = (
                     ),
                 );
             } else {
-                const existingNotices = existingConversion.notices || [];
-                const newNotices = newConversion.notices || [];
-
                 converted.set(changes.ruleName, {
                     ...existingConversion,
                     ruleArguments: merger(
                         existingConversion.ruleArguments,
                         newConversion.ruleArguments,
                     ),
-                    notices: [...existingNotices, ...newNotices],
+                    notices: Array.from(
+                        new Set([...existingConversion.notices, ...newConversion.notices]),
+                    ),
                 });
             }
         }