feat: add rxjs-prefer-angular-takeuntil-before-subscribe rule

.gitignore

@@ -3,3 +3,4 @@ yarn-error.log
 /dist
 /node_modules
 /temp
+/.idea

README.md

@@ -117,6 +117,7 @@ The package includes the following rules (none of which are enabled by default):
 | `rxjs-no-unsafe-takeuntil` | Disallows the application of operators after `takeUntil`. Operators placed after `takeUntil` can effect [subscription leaks](https://medium.com/@cartant/rxjs-avoiding-takeuntil-leaks-fb5182d047ef). | [See below](#rxjs-no-unsafe-takeuntil) |
 | `rxjs-no-unused-add` | Disallows the importation of patched observables or operators that are not used in the module. | None |
 | `rxjs-no-wholesale` | Disallows the wholesale importation of `rxjs` or `rxjs/Rx`. | None |
+| `rxjs-prefer-angular-takeuntil-before-subscribe` | Enforces the application of the `takeUntil` operator when calling of `subscribe` within an Angular component. | [See below](#rxjs-prefer-angular-takeuntil-before-subscribe) |
 | `rxjs-prefer-angular-async-pipe` | Disallows the calling of `subscribe` within an Angular component. | None |
 | `rxjs-prefer-observer` | Enforces the passing of observers to `subscribe` and `tap`. See [this RxJS issue](https://github.com/ReactiveX/rxjs/issues/4159). | [See below](#rxjs-prefer-observer) |
 | `rxjs-suffix-subjects` | Disalllows subjects that don't end with the specified `suffix` option. | [See below](#rxjs-suffix-subjects) |
@@ -395,6 +396,59 @@ The following options are equivalent to the rule's default configuration:
 }
 ```
 
+<a name="rxjs-prefer-angular-takeuntil-before-subscribe"></a>
+
+#### rxjs-prefer-angular-takeuntil-before-subscribe
+
+This rule tries to avoid memory leaks in angular components when calling `.subscribe()` without properly unsubscribing 
+by enforcing the application of the `takeUntil(this.destroy$)` operator before the `.subscribe()` 
+as well as before certain operators (`publish`, `publishBehavior`, `publishLast`, `publishReplay`, `shareReplay`)
+and ensuring the component implements the `ngOnDestroy` 
+method invoking `this.destroy$.next()` and `this.destroy$.complete()`.
+
+##### Example
+This should trigger an error:
+```typescript
+@Component({
+  selector: 'app-my',
+  template: '<div>{{k$ | async}}</div>'
+})
+class MyComponent {
+      ~~~~~~~~~~~    component containing subscribe must implement the ngOnDestroy() method
+
+
+    k$ = a.pipe(shareReplay(1));
+                ~~~~~~~~~~~~~~   the shareReplay operator used within a component must be preceded by takeUntil
+
+    someMethod() {
+        const e = a.pipe(switchMap(_ => b)).subscribe();
+                                            ~~~~~~~~~      subscribe within a component must be preceded by takeUntil
+    }
+}
+```
+
+while this should be fine:
+```typescript
+@Component({
+  selector: 'app-my',
+  template: '<div>{{k$ | async}}</div>'
+})
+class MyComponent implements SomeInterface, OnDestroy {
+    private destroy$: Subject<void> = new Subject<void>();
+
+    k$ = a.pipe(takeUntil(this.destroy$), shareReplay(1));
+
+    someMethod() {
+        const e = a.pipe(switchMap(_ => b), takeUntil(this.destroy$)).subscribe();
+    }
+
+    ngOnDestroy() {
+      this.destroy$.next();
+      this.destroy$.complete();
+    }
+}
+```
+
 <a name="rxjs-prefer-observer"></a>
 
 #### rxjs-prefer-observer

docs/index.md

@@ -53,6 +53,7 @@ The package includes the following rules (none of which are enabled by default):
 | `rxjs-no-unsafe-takeuntil` | Disallows the application of operators after `takeUntil`. Operators placed after `takeUntil` can effect [subscription leaks](https://medium.com/@cartant/rxjs-avoiding-takeuntil-leaks-fb5182d047ef). | [See below](#rxjs-no-unsafe-takeuntil) |
 | `rxjs-no-unused-add` | Disallows the importation of patched observables or operators that are not used in the module. | None |
 | `rxjs-no-wholesale` | Disallows the wholesale importation of `rxjs` or `rxjs/Rx`. | None |
+| `rxjs-prefer-angular-takeuntil-before-subscribe` | Enforces the application of the `takeUntil` operator when calling of `subscribe` within an Angular component. | [See below](#rxjs-prefer-angular-takeuntil-before-subscribe) |
 | `rxjs-prefer-angular-async-pipe` | Disallows the calling of `subscribe` within an Angular component. | None |
 | `rxjs-prefer-observer` | Enforces the passing of observers to `subscribe` and `tap`. See [this RxJS issue](https://github.com/ReactiveX/rxjs/issues/4159). | [See below](#rxjs-prefer-observer) |
 | `rxjs-suffix-subjects` | Disalllows subjects that don't end with the specified `suffix` option. | [See below](#rxjs-suffix-subjects) |
@@ -331,6 +332,62 @@ The following options are equivalent to the rule's default configuration:
 }
 ```
 
+<a name="rxjs-angular-prefer-takeuntil-before-subscribe"></a>
+
+
+<a name="rxjs-prefer-angular-takeuntil-before-subscribe"></a>
+
+#### rxjs-prefer-angular-takeuntil-before-subscribe
+
+This rule tries to avoid memory leaks in angular components when calling `.subscribe()` without properly unsubscribing 
+by enforcing the application of the `takeUntil(this.destroy$)` operator before the `.subscribe()` 
+as well as before certain operators (`publish`, `publishBehavior`, `publishLast`, `publishReplay`, `shareReplay`)
+and ensuring the component implements the `ngOnDestroy` 
+method invoking `this.destroy$.next()` and `this.destroy$.complete()`.
+
+##### Example
+This should trigger an error:
+```typescript
+@Component({
+  selector: 'app-my',
+  template: '<div>{{k$ | async}}</div>'
+})
+class MyComponent {
+      ~~~~~~~~~~~    component containing subscribe must implement the ngOnDestroy() method
+
+
+    k$ = a.pipe(shareReplay(1));
+                ~~~~~~~~~~~~~~   the shareReplay operator used within a component must be preceded by takeUntil
+
+    someMethod() {
+        const e = a.pipe(switchMap(_ => b)).subscribe();
+                                            ~~~~~~~~~      subscribe within a component must be preceded by takeUntil
+    }
+}
+```
+
+while this should be fine:
+```typescript
+@Component({
+  selector: 'app-my',
+  template: '<div>{{k$ | async}}</div>'
+})
+class MyComponent implements SomeInterface, OnDestroy {
+    private destroy$: Subject<void> = new Subject<void>();
+
+    k$ = a.pipe(takeUntil(this.destroy$), shareReplay(1));
+
+    someMethod() {
+        const e = a.pipe(switchMap(_ => b), takeUntil(this.destroy$)).subscribe();
+    }
+
+    ngOnDestroy() {
+      this.destroy$.next();
+      this.destroy$.complete();
+    }
+}
+```
+
 <a name="rxjs-prefer-observer"></a>
 
 #### rxjs-prefer-observer