feat(challenge26): forbidden enum rule

README.md

@@ -80,6 +80,7 @@ If you would like to propose a challenge, this project is open source, so feel f
 
 <a href="./libs/custom-plugin/src/generators/custom-library/README.md"><img src="https://img.shields.io/badge/25-Extends Nx Library generator-red" alt="extends lib generator"/></a>
 <a href="./libs/custom-plugin/src/generators/feature-component/README.md"><img src="https://img.shields.io/badge/25-Component generator-orange" alt="Custom component generator"/></a>
+<a href="./tools/eslint-rules/rules/forbidden-enum.README.md"><img src="https://img.shields.io/badge/26-Forbid enum Rule-green" alt="Forbid enum rules"/></a>
 
 ## Contributors ✨
 
@@ -89,7 +90,7 @@ If you would like to propose a challenge, this project is open source, so feel f
 <table>
   <tbody>
     <tr>
-      <td align="center" valign="top" width="14.28%"><a href="https://medium.com/@thomas.laforge"><img src="https://avatars.githubusercontent.com/u/30832608?s…00&u=6f0ad9676792f29fd7fe6e113df06213d384a813&v=4" width="100px;" alt="Thomas Laforge"/><br /><sub><b>Thomas Laforge</b></sub></a><br />25 🧩</a></td>
+      <td align="center" valign="top" width="14.28%"><a href="https://medium.com/@thomas.laforge"><img src="https://avatars.githubusercontent.com/u/30832608?s…00&u=6f0ad9676792f29fd7fe6e113df06213d384a813&v=4" width="100px;" alt="Thomas Laforge"/><br /><sub><b>Thomas Laforge</b></sub></a><br />26 🧩</a></td>
     </tr>
   </tbody>
 </table>

nx.json

@@ -27,7 +27,11 @@
       "inputs": ["default", "^production"]
     },
     "lint": {
-      "inputs": ["default", "{workspaceRoot}/.eslintrc.json"]
+      "inputs": [
+        "default",
+        "{workspaceRoot}/.eslintrc.json",
+        "{workspaceRoot}/tools/eslint-rules/**/*"
+      ]
     },
     "component-test": {
       "inputs": ["default", "^production"]

tools/eslint-rules/index.ts

@@ -0,0 +1,8 @@
+import {
+  rule as forbiddenEnum,
+  RULE_NAME as forbiddenEnumName,
+} from './rules/forbidden-enum';
+
+module.exports = {
+  rules: { [forbiddenEnumName]: forbiddenEnum },
+};

tools/eslint-rules/jest.config.ts

@@ -0,0 +1,13 @@
+/* eslint-disable */
+export default {
+  displayName: 'eslint-rules',
+  preset: '../../jest.preset.js',
+  transform: {
+    '^.+\\.[tj]s$': ['ts-jest', { tsconfig: '<rootDir>/tsconfig.spec.json' }],
+  },
+  moduleFileExtensions: ['ts', 'js', 'html'],
+  coverageDirectory: '../../coverage/tools/eslint-rules',
+  moduleNameMapper: {
+    '@eslint/eslintrc': '@eslint/eslintrc/dist/eslintrc-universal.cjs',
+  },
+};

tools/eslint-rules/project.json

@@ -0,0 +1,21 @@
+{
+  "name": "eslint-rules",
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "sourceRoot": "tools/eslint-rules",
+  "targets": {
+    "test": {
+      "executor": "@nx/jest:jest",
+      "outputs": ["{workspaceRoot}/coverage/{projectRoot}"],
+      "options": {
+        "jestConfig": "tools/eslint-rules/jest.config.ts",
+        "passWithNoTests": true
+      },
+      "configurations": {
+        "ci": {
+          "ci": true,
+          "codeCoverage": true
+        }
+      }
+    }
+  }
+}

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

@@ -0,0 +1,34 @@
+<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

@@ -0,0 +1,11 @@
+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

@@ -0,0 +1,37 @@
+/**
+ * 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 {};
+  },
+});

tools/eslint-rules/tsconfig.json

@@ -0,0 +1,16 @@
+{
+  "extends": "../../tsconfig.base.json",
+  "compilerOptions": {
+    "module": "commonjs"
+  },
+  "files": [],
+  "include": [],
+  "references": [
+    {
+      "path": "./tsconfig.lint.json"
+    },
+    {
+      "path": "./tsconfig.spec.json"
+    }
+  ]
+}

tools/eslint-rules/tsconfig.lint.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "types": ["node"]
+  },
+  "exclude": ["**/*.spec.ts"],
+  "include": ["**/*.ts"]
+}

tools/eslint-rules/tsconfig.spec.json

@@ -0,0 +1,9 @@
+{
+  "extends": "./tsconfig.json",
+  "compilerOptions": {
+    "outDir": "../../dist/out-tsc",
+    "module": "commonjs",
+    "types": ["jest", "node"]
+  },
+  "include": ["jest.config.ts", "**/*.test.ts", "**/*.spec.ts", "**/*.d.ts"]
+}