fix(mem-leak): Fix potential memory leaks. (#15308)

Author: MayaKirova

projects/igniteui-angular/src/lib/directives/button/button.directive.ts

@@ -7,7 +7,8 @@ import {
     Output,
     Renderer2,
     booleanAttribute,
-    AfterContentInit
+    AfterContentInit,
+    OnDestroy
 } from '@angular/core';
 import { mkenum } from '../../core/utils';
 import { IBaseEventArgs } from '../../core/utils';
@@ -46,7 +47,7 @@ export type IgxButtonType = typeof IgxButtonType[keyof typeof IgxButtonType];
     selector: '[igxButton]',
     standalone: true
 })
-export class IgxButtonDirective extends IgxButtonBaseDirective implements AfterContentInit {
+export class IgxButtonDirective extends IgxButtonBaseDirective implements AfterContentInit, OnDestroy {
     private static ngAcceptInputType_type: IgxButtonType | '';
 
     /**
@@ -92,6 +93,12 @@ export class IgxButtonDirective extends IgxButtonBaseDirective implements AfterC
      */
     private _selected = false;
 
+    private emitSelected() {
+        this.buttonSelected.emit({
+            button: this
+        });
+    }
+
     /**
      * Gets or sets whether the button is selected.
      * Mainly used in the IgxButtonGroup component and it will have no effect if set separately.
@@ -121,11 +128,11 @@ export class IgxButtonDirective extends IgxButtonBaseDirective implements AfterC
     }
 
     public ngAfterContentInit() {
-        this.nativeElement.addEventListener('click', () => {
-            this.buttonSelected.emit({
-                button: this
-            });
-        });
+        this.nativeElement.addEventListener('click', this.emitSelected.bind(this));
+    }
+
+    public ngOnDestroy(): void {
+        this.nativeElement.removeEventListener('click', this.emitSelected);
     }
 
     /**

projects/igniteui-angular/src/lib/input-group/input-group.component.ts

@@ -219,15 +219,13 @@ export class IgxInputGroupComponent implements IgxInputGroupBase, AfterViewInit
         private themeToken: ThemeToken
     ) {
         this._theme = this.themeToken.theme;
-
-        const { unsubscribe } = this.themeToken.onChange((theme) => {
+        const themeChange = this.themeToken.onChange((theme) => {
             if (this._theme !== theme) {
                 this._theme = theme;
                 this.cdr.detectChanges();
             }
         });
-
-        this._destroyRef.onDestroy(() => unsubscribe);
+        this._destroyRef.onDestroy(() => themeChange.unsubscribe());
     }
 
     /** @hidden */