Add no-unused-variable converter (#422)

* Add no-unused-variable converter

* remove extra rule output on no-unused-variable

Author: KingDarBoja

src/rules/converters/no-unused-variable.ts

@@ -0,0 +1,16 @@
+import { RuleConverter } from "../converter";
+
+export const NO_UNUSED_VARIABLE_NOTICE =
+    "Please read the following article as the rule behaviour may change on the short term: " +
+    "https://github.com/typescript-eslint/typescript-eslint/issues/1856";
+
+export const convertNoUnusedVariable: RuleConverter = () => {
+    return {
+        rules: [
+            {
+                ruleName: "@typescript-eslint/no-unused-vars",
+                notices: [NO_UNUSED_VARIABLE_NOTICE],
+            },
+        ],
+    };
+};

src/rules/converters/tests/no-unused-variable.test.ts

@@ -0,0 +1,18 @@
+import { convertNoUnusedVariable, NO_UNUSED_VARIABLE_NOTICE } from "../no-unused-variable";
+
+describe(convertNoUnusedVariable, () => {
+    test("conversion without arguments", () => {
+        const result = convertNoUnusedVariable({
+            ruleArguments: [],
+        });
+
+        expect(result).toEqual({
+            rules: [
+                {
+                    ruleName: "@typescript-eslint/no-unused-vars",
+                    notices: [NO_UNUSED_VARIABLE_NOTICE],
+                },
+            ],
+        });
+    });
+});

src/rules/rulesConverters.ts

@@ -99,6 +99,7 @@ import { convertNoUnnecessarySemicolons } from "./converters/no-unnecessary-semi
 import { convertNoUnnecessaryTypeAssertion } from "./converters/no-unnecessary-type-assertion";
 import { convertNoUnsafeFinally } from "./converters/no-unsafe-finally";
 import { convertNoUnusedExpression } from "./converters/no-unused-expression";
+import { convertNoUnusedVariable } from "./converters/no-unused-variable";
 import { convertNoUseBeforeDeclare } from "./converters/no-use-before-declare";
 import { convertNoVarKeyword } from "./converters/no-var-keyword";
 import { convertNoVarRequires } from "./converters/no-var-requires";
@@ -241,6 +242,7 @@ export const rulesConverters = new Map([
     ["no-unnecessary-type-assertion", convertNoUnnecessaryTypeAssertion],
     ["no-unsafe-finally", convertNoUnsafeFinally],
     ["no-unused-expression", convertNoUnusedExpression],
+    ["no-unused-variable", convertNoUnusedVariable],
     ["no-use-before-declare", convertNoUseBeforeDeclare],
     ["no-var-keyword", convertNoVarKeyword],
     ["no-var-requires", convertNoVarRequires],