docs: add docs for new rule and update README

README.md

@@ -46,11 +46,12 @@ The "recommended" preset contains the rules listed below. If you need custom con
 
 ## Rules
 
-| Rule                                                                                 | Description                                                    | Recommended |
+| Rule                                                                                 | Description                                                    | Type |
 | ------------------------------------------------------------------------------------ | -------------------------------------------------------------- | ----------- |
-| [`@trilon/enforce-close-testing-module`](docs/rules/enforce-close-testing-module.md) | Ensures NestJS testing modules are closed properly after tests | ✅          |
-| [`@trilon/check-inject-decorator`](docs/rules/check-inject-decorator.md)             | Detects incorrect usage of `@Inject(TOKEN)` decorator          | ✅          |
-| [`@trilon/detect-circular-reference`](docs/rules/detect-circular-reference.md)       | Detects usage of `forwardRef()` method                         | ✅          |
+| [`@trilon/enforce-close-testing-module`](docs/rules/enforce-close-testing-module.md) | Ensures NestJS testing modules are closed properly after tests | Recommended ✅          |
+| [`@trilon/check-inject-decorator`](docs/rules/check-inject-decorator.md)             | Detects incorrect usage of `@Inject(TOKEN)` decorator          | Recommended ✅          |
+| [`@trilon/detect-circular-reference`](docs/rules/detect-circular-reference.md)       | Detects usage of `forwardRef()` method                         | Recommended ✅          |
+| [`@trilon/enforce-custom-provider-type`](docs/rules/enforce-custom-provider-type.md) | Enforces a styleguide for provider types                       | Strict ⚠️          |
 ---
 
 # Trilon Consulting 

docs/rules/enforce-custom-provider-type.md

@@ -0,0 +1,55 @@
+---
+description: 'Enforces a styleguide for provider types'
+---
+
+Large teams can have the desire to limit or enforce a particular style of creating [custom providers](https://docs.nestjs.com/fundamentals/custom-providers); e.g. banning request-scoped providers to avoid potential circular dependencies, or [preferring factory providers over value providers to significantly increase performance](https://github.com/nestjs/nest/pull/12753). This rule enforces a particular type of provider to be used.
+
+## Options
+
+This rule accepts an object with the "prefer" property, which might be one of the following values:
+
+- `value`: Enforces the use of value providers.
+- `factory`: Enforces the use of factory providers.
+- `class`: Enforces the use of class providers.
+- `existing`: Enforces the use of existing providers.
+
+
+### Example of Options
+
+```json
+"rules": {
+  "@trilon/enforce-custom-provider-type": [ 
+   "warn", {  
+     "prefer": "factory"
+   }
+  ]
+}
+```
+
+## Examples
+Considering the options above, the following examples will show how the rule behaves when the `prefer` option is set to `factory`.
+
+### ❌ Incorrect
+
+```ts
+const customValueProvider: Provider = {
+  provide: 'TOKEN',
+  useValue: 'some-value' // ⚠️ provider is not of type "factory"
+}
+
+const customClassProvider: Provider = {
+  provide: AbstractClass,
+  useClass: SomeClass  // ⚠️ provider is not of type "factory"
+}
+```
+
+### ✅ Correct
+
+const factoryProvider: Provider = {
+  provide: 'TOKEN',
+  useFactory: () => 'some-value'
+}
+
+## When Not To Use It
+
+If you don't want to enforce a particular style of provider, you can disable this rule.

src/index.ts

@@ -1,6 +1,7 @@
 import enforceCloseTestingModuleRule from './rules/enforce-close-testing-module.rule';
 import checkInjectDecoratorRule from './rules/check-inject-decorator.rule';
 import detectCircularReferenceRule from './rules/detect-circular-reference.rule';
+import enforceCustomProviderTypeRule from './rules/enforce-custom-provider-type.rule';
 // TODO: we should type this as ESLint.Plugin but there's a type incompatibilities with the utils package
 const plugin = {
   configs: {
@@ -11,11 +12,20 @@ const plugin = {
         '@trilon/detect-circular-reference': 'warn',
       },
     },
+    strict: {
+      rules: {
+        '@trilon/enforce-close-testing-module': 'error',
+        '@trilon/check-inject-decorator': 'error',
+        '@trilon/detect-circular-reference': 'error',
+        '@trilon/enforce-custom-provider-type': 'error',
+      },
+    },
   },
   rules: {
     'enforce-close-testing-module': enforceCloseTestingModuleRule,
     'check-inject-decorator': checkInjectDecoratorRule,
     'detect-circular-reference': detectCircularReferenceRule,
+    '@trilon/enforce-custom-provider-type': enforceCustomProviderTypeRule,
   },
 };