feat(challenge26): forbidden enum rule

tools/eslint-rules/rules/forbidden-enum.README.md

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+<h1>Create a eslint rule to forbid enums</h1>
+
+> Author: Thomas Laforge
+
+### Information
+
+Eslint is an amazing tool that helps developers avoid simple mistakes and adhere to company style guides.
+
+In this first example, we will create a rule that forbids the use of enums. The rule will suggest using string unions instead of enums whenever you add an enum to your code. It is a straightforward rule for learning how to create rules.
+
+You will also need to write tests to verify the rule's functionality.
+
+To test the rule inside your project, add `"@nrwl/nx/workspace/forbidden-enum": "error"` to the `eslintrc.json` file and attempt to insert an enum into any project to witness the magic. 😇
+
+To assist you with AST (Abstract Syntax Tree) definitions, you can visit the [AST explorer](https://astexplorer.net/) and use JavaScript, @typescript-eslint/parser, and Eslint-v8 as the transformation method. However, please note that you will only get the type information there. The transformation function may not work for TypeScript types since the editor is in JavaScript.
+
+You can also check this [repo](https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin/src/rules) for eslint rule examples.
+
+### Submitting your work
+
+1. Fork the project
+2. clone it
+3. npm ci
+4. _...work on it_
+5. `npx nx test eslint-rules`
+6. Commit your work
+7. Submit a PR with a title beginning with **Answer:27** that I will review and other dev can review.
+
+<a href="https://github.com/tomalaforge/angular-challenges/pulls?q=label%3A27+label%3Aanswer"><img src="https://img.shields.io/badge/-Solutions-green" alt="forbidden-enum"/></a>
+<a href='https://github.com/tomalaforge/angular-challenges/pulls?q=label%3A27+label%3A"answer+author"'><img src="https://img.shields.io/badge/-Author solution-important" alt="forbidden-enum solution author"/></a>
+
+<!-- <a href="{Blog post url}" target="_blank" rel="noopener noreferrer"><img src="https://img.shields.io/badge/-Blog post explanation-blue" alt="forbidden-enum blog article"/></a> -->
+
+_You can ask any question on_ <a href="https://twitter.com/laforge_toma" target="_blank" rel="noopener noreferrer"><img src="./../../../logo/twitter.svg" height=20px alt="twitter"/></a>

tools/eslint-rules/rules/forbidden-enum.spec.ts

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+import { TSESLint } from '@typescript-eslint/utils';
+import { rule, RULE_NAME } from './forbidden-enum';
+
+const ruleTester = new TSESLint.RuleTester({
+  parser: require.resolve('@typescript-eslint/parser'),
+});
+
+ruleTester.run(RULE_NAME, rule, {
+  valid: [`const example = true;`],
+  invalid: [],
+});

tools/eslint-rules/rules/forbidden-enum.ts

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+/**
+ * This file sets you up with structure needed for an ESLint rule.
+ *
+ * It leverages utilities from @typescript-eslint to allow TypeScript to
+ * provide autocompletions etc for the configuration.
+ *
+ * Your rule's custom logic will live within the create() method below
+ * and you can learn more about writing ESLint rules on the official guide:
+ *
+ * https://eslint.org/docs/developer-guide/working-with-rules
+ *
+ * You can also view many examples of existing rules here:
+ *
+ * https://github.com/typescript-eslint/typescript-eslint/tree/master/packages/eslint-plugin/src/rules
+ */
+
+import { ESLintUtils } from '@typescript-eslint/utils';
+
+// NOTE: The rule will be available in ESLint configs as "@nx/workspace/forbidden-enum"
+export const RULE_NAME = 'forbidden-enum';
+
+export const rule = ESLintUtils.RuleCreator(() => __filename)({
+  name: RULE_NAME,
+  meta: {
+    type: 'problem',
+    docs: {
+      description: ``,
+      recommended: 'error',
+    },
+    schema: [],
+    messages: {},
+  },
+  defaultOptions: [],
+  create(context) {
+    return {};
+  },
+});