Use lifecycle hooks to unsubscribe

src/app/app.component.ts

-import { Component, ChangeDetectionStrategy, OnInit, ViewEncapsulation } from '@angular/core';
+import { Component, ChangeDetectionStrategy, OnDestroy, OnInit, ViewEncapsulation } from '@angular/core';
 
 import { TranslateService } from 'ng2-translate';
 
@@ -9,7 +9,7 @@ import { TranslateService } from 'ng2-translate';
   templateUrl: './app.component.html',
   styleUrls: ['./app.component.scss']
 })
-export class AppComponent implements OnInit {
+export class AppComponent implements OnDestroy, OnInit {
 
   example: string;
 
@@ -18,6 +18,8 @@ export class AppComponent implements OnInit {
     recipient: 'World'
   }
 
+  private registerSubscription: any;
+
   constructor(public translate: TranslateService) {
     // this language will be used as a fallback when a translation isn't found in the current language
     translate.setDefaultLang('en');
@@ -26,9 +28,15 @@ export class AppComponent implements OnInit {
   }
 
   ngOnInit() {
-    this.translate.get('example.with.data', { greeting: 'Hello', recipient: 'DSpace' }).subscribe((res: string) => {
-      this.example = res;
+    this.registerSubscription = this.translate.get('example.with.data', { greeting: 'Hello', recipient: 'DSpace' }).subscribe((translation: string) => {
+      this.example = translation;
     });
   }
 
+  ngOnDestroy() {
+    if (this.registerSubscription) {
+      this.registerSubscription.unsubscribe();
+    }
+  }
+
 }