fix(theme): save theme in local storage after theme changing

src/app/@core/utils/theme.service.ts

@@ -1,6 +1,7 @@
 import {Injectable, OnDestroy} from '@angular/core';
 import {Observable} from 'rxjs';
 import {takeWhile} from 'rxjs/operators';
+import {environment} from '../../../environments/environment';
 
 @Injectable()
 export class CurrentThemeService implements OnDestroy {
@@ -10,6 +11,22 @@ export class CurrentThemeService implements OnDestroy {
     subscriber.next(localStorage.theme);
   }).pipe(takeWhile(() => this.alive));
 
+  setCurrentTheme(themeName: string): void {
+    const currentTheme = {
+      themeName: themeName,
+      expires_in: this.calculateExpiration(environment.currentThemeLife),
+    };
+
+    localStorage.setItem('theme', JSON.stringify(currentTheme));
+  }
+
+  calculateExpiration(iat: number): number {
+    const currentDate = new Date().getTime();
+    const timestamp = iat || Math.floor(Date.now() / 1000);
+
+    return Math.floor(timestamp + currentDate);
+  }
+
   ngOnDestroy(): void {
     this.alive = false;
   }

src/app/@theme/components/header/header.component.ts

@@ -6,6 +6,7 @@ import { AnalyticsService, LayoutService } from '../../../@core/utils';
 import { map, takeUntil } from 'rxjs/operators';
 import { Subject, Observable } from 'rxjs';
 import { RippleService } from '../../../@core/utils/ripple.service';
+import {CurrentThemeService} from '../../../@core/utils/theme.service';
 
 @Component({
   selector: 'ngx-header',
@@ -59,6 +60,7 @@ export class HeaderComponent implements OnInit, OnDestroy {
     private breakpointService: NbMediaBreakpointsService,
     private rippleService: RippleService,
     private analytics: AnalyticsService,
+    private currentThemeService: CurrentThemeService,
   ) {
     this.materialTheme$ = this.themeService.onThemeChange()
       .pipe(map(theme => {
@@ -99,6 +101,7 @@ export class HeaderComponent implements OnInit, OnDestroy {
   }
 
   changeTheme(themeName: string) {
+    this.currentThemeService.setCurrentTheme(themeName);
     this.themeService.changeTheme(themeName);
   }
 

src/app/themes-screen/starter.component.ts

@@ -2,7 +2,7 @@ import {Component, OnDestroy} from '@angular/core';
 import {NbMediaBreakpoint, NbThemeService} from '@nebular/theme';
 import {Router} from '@angular/router';
 import {AnalyticsService} from '../@core/utils';
-import { environment } from '../../environments/environment';
+import {CurrentThemeService} from '../@core/utils/theme.service';
 
 @Component({
   selector: 'ngx-starter',
@@ -41,18 +41,13 @@ export class NgxStarterComponent implements OnDestroy {
   ];
 
   constructor(private router: Router,
-              protected themeService: NbThemeService,
+              private themeService: NbThemeService,
+              private currentThemeService: CurrentThemeService,
               private analytics: AnalyticsService,
               ) {}
 
   navigate(themeName: string) {
-    const currentTheme = {
+    this.currentThemeService.setCurrentTheme(themeName);
-      themeName: themeName,
-      expires_in: this.calculateExpiration(environment.currentThemeLife),
-    };
-
-    localStorage.setItem('theme', JSON.stringify(currentTheme));
-
     this.themeService.changeTheme(themeName);
     this.router.navigate(['/pages/dashboard'], {queryParams: {theme: themeName}});
   }
@@ -63,11 +58,4 @@ export class NgxStarterComponent implements OnDestroy {
 
   ngOnDestroy() {
   }
-
-  calculateExpiration(iat: number): number {
-    const currentDate = new Date().getTime();
-    const timestamp = iat || Math.floor(Date.now() / 1000);
-
-    return Math.floor(timestamp + currentDate);
-  }
 }