diff --git a/src/app/collaborateurs/collaborateurs.component.ts b/src/app/collaborateurs/collaborateurs.component.ts
index eff7602..f9dc960 100644
--- a/src/app/collaborateurs/collaborateurs.component.ts
+++ b/src/app/collaborateurs/collaborateurs.component.ts
@@ -88,7 +88,7 @@ export class CollaborateursComponent implements OnInit {
   }
 
   ngOnDestroy() {
-    if(this.collaborateursDisponiblesSubscription != null) {
+    if(this.collaborateursDisponiblesSubscription != undefined) {
       this.collaborateursDisponiblesSubscription.unsubscribe();
     }
   }
diff --git a/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.html b/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.html
index e669227..3c923f8 100644
--- a/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.html
+++ b/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.html
@@ -1,11 +1,11 @@
 <app-nav-menu></app-nav-menu>
-<ng-container *ngIf="collaborateur!=null">
+<ng-container *ngIf="collaborateur!=undefined">
   <h2>{{ collaborateur.prenom }} {{ collaborateur.nom }} </h2>
 
   <h3>Agence : {{ collaborateur.businessUnit.nom}}</h3>
   <h3>Date embauche : {{ collaborateur.dateArrive}}</h3>
 </ng-container>
-<ng-container *ngIf="collaborateur==null || !eploaded">
+<ng-container *ngIf="collaborateur==undefined || !eploaded">
   <mat-spinner></mat-spinner>
 </ng-container>
 
diff --git a/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.ts b/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.ts
index a74b43a..10c7091 100644
--- a/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.ts
+++ b/src/app/collaborateurs/details-collaborateur/details-collaborateur.component.ts
@@ -76,10 +76,10 @@ export class DetailsCollaborateurComponent implements OnInit {
   }
 
   ngOnDestroy() {
-    if(this.epSubscription!= null) {
+    if(this.epSubscription!= undefined) {
       this.epSubscription.unsubscribe();
     }
-    if(this.collaborateurSubscription!= null) {
+    if(this.collaborateurSubscription!= undefined) {
       this.collaborateurSubscription.unsubscribe();
     }
   }
diff --git a/src/app/home/home-assistante/home-assistante.component.ts b/src/app/home/home-assistante/home-assistante.component.ts
index f5da583..c7c89ed 100644
--- a/src/app/home/home-assistante/home-assistante.component.ts
+++ b/src/app/home/home-assistante/home-assistante.component.ts
@@ -176,7 +176,7 @@ export class HomeAssistanteComponent implements OnInit, AfterViewInit {
     * Détruire toutes les Subscriptions utilisées pour libérer de la mémoire après le changement de page.
     */
   ngOnDestroy() {
-    if(this.epDisponiblesSubscription != null) {
+    if(this.epDisponiblesSubscription != undefined) {
       this.epDisponiblesSubscription.unsubscribe();
     }
   }
diff --git a/src/app/referents/details-referent/details-referent.component.html b/src/app/referents/details-referent/details-referent.component.html
index 249071e..82352ef 100644
--- a/src/app/referents/details-referent/details-referent.component.html
+++ b/src/app/referents/details-referent/details-referent.component.html
@@ -1,7 +1,7 @@
 <app-nav-menu></app-nav-menu>
-<ng-container  *ngIf="referent!=null">
+<ng-container  *ngIf="referent!=undefined">
   <h2> {{referent.prenom }} {{referent.nom }} ({{referent.businessUnit.nom }}) </h2>
 </ng-container>
-<ng-container *ngIf="referent==null">
+<ng-container *ngIf="referent==undefined">
   <mat-spinner></mat-spinner>
 </ng-container>
diff --git a/src/app/referents/details-referent/details-referent.component.ts b/src/app/referents/details-referent/details-referent.component.ts
index 6dd9dfa..feb94cb 100644
--- a/src/app/referents/details-referent/details-referent.component.ts
+++ b/src/app/referents/details-referent/details-referent.component.ts
@@ -39,7 +39,7 @@ export class DetailsReferentComponent implements OnInit {
   }
 
   ngOnDestroy() {
-    if(this.referentSubscription!=null) {
+    if(this.referentSubscription!=undefined) {
       this.referentSubscription.unsubscribe();
     }
   }
diff --git a/src/app/referents/referents.component.ts b/src/app/referents/referents.component.ts
index 18c1930..f864b2e 100644
--- a/src/app/referents/referents.component.ts
+++ b/src/app/referents/referents.component.ts
@@ -73,7 +73,7 @@ export class ReferentsComponent implements OnInit {
   }
 
   ngOnDestroy() {
-    if(this.referentsDisponiblesSubscription != null) {
+    if(this.referentsDisponiblesSubscription != undefined) {
       this.referentsDisponiblesSubscription.unsubscribe();
     }
   }