Add missing no-shadow rule for typescript

rules/__fixtures__/typescript/no-shadow.ts

@@ -0,0 +1,12 @@
+enum DisplayType {
+  CARDS = 'cards',
+  LIST = 'list',
+  ICONS = 'icons'
+}
+
+export const display: DisplayType = DisplayType.ICONS;
+
+export function toggleType(next = DisplayType): DisplayType {
+  const display = next;
+  return display;
+}

rules/typescript.js

@@ -32,6 +32,14 @@ module.exports = {
         },
       },
       rules: {
+        // Enforce no variable declarations from shadowing variables declared in
+        // the outer scope: This rule extends the base eslint/no-shadow rule. It
+        // adds support for TypeScript's this parameters and global augmentation,
+        // and adds options for TypeScript features.
+        // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-shadow.md
+        '@typescript-eslint/no-shadow': 'error',
+        'no-shadow': 'off',
+
         // Enforce no unused vars: This rule extends the base "eslint/no-unused-vars"
         // rule. It adds support for TypeScript features, such as types.
         // https://github.com/typescript-eslint/typescript-eslint/blob/master/packages/eslint-plugin/docs/rules/no-unused-vars.md

rules/typescript.test.js

@@ -20,6 +20,30 @@ describe('typescript rules', () => {
     linter = null;
   });
 
+  describe('no-shadow', () => {
+    it('should error', async () => {
+      const filePath = join(__dirname, '__fixtures__', 'typescript', 'no-shadow.ts');
+      const [{ messages, ...rest }] = await linter.lintFiles([filePath]);
+
+      expect(messages).toEqual([
+        expect.objectContaining({
+          line: 10,
+          messageId: 'noShadow',
+          ruleId: '@typescript-eslint/no-shadow',
+        }),
+      ]);
+
+      expect(rest).toEqual(
+        expect.objectContaining({
+          errorCount: 1,
+          warningCount: 0,
+          fixableErrorCount: 0,
+          fixableWarningCount: 0,
+        }),
+      );
+    });
+  });
+
   describe('no-unused-vars', () => {
     it('should error', async () => {
       const filePath = join(__dirname, '__fixtures__', 'typescript', 'no-unused-vars.ts');
@@ -67,12 +91,11 @@ describe('typescript rules', () => {
           messageId: 'noUseBeforeDefine',
           ruleId: '@typescript-eslint/no-use-before-define',
         }),
-        expect.any(Object),
       ]);
 
       expect(rest).toEqual(
         expect.objectContaining({
-          errorCount: 2,
+          errorCount: 1,
           warningCount: 0,
           fixableErrorCount: 0,
           fixableWarningCount: 0,