create service to manage persistant configuration

src/renderer/services/configuration.service.ts

@@ -0,0 +1,40 @@
+import { BehaviorSubject } from "rxjs";
+
+export class ConfigurationService {
+    
+    private static instance: ConfigurationService;
+    private subscribers: Map<string, BehaviorSubject<any>[]>;
+    
+    private constructor(){
+        this.subscribers = new Map<string, BehaviorSubject<any>[]>();
+    }
+
+    public static getInstance(): ConfigurationService{
+        if(!ConfigurationService.instance){ ConfigurationService.instance = new ConfigurationService(); }
+        return ConfigurationService.instance;
+    }
+
+    public get<Type>(key: string): Type{
+        const t = JSON.parse(window.localStorage.getItem(key));
+        return t;
+    }
+
+    public set(key: string, value: any){
+        window.localStorage.setItem(key, JSON.stringify(value));
+        if(this.subscribers.has(key)){
+            this.subscribers.get(key).forEach(sub => sub.next(value));
+        }
+    }
+
+    public watch(key: string): BehaviorSubject<any>{
+        const newSub = new BehaviorSubject(this.get(key));
+        if(!this.subscribers.has(key)){ this.subscribers.set(key, []); }
+        this.subscribers.get(key).push(newSub);
+        return newSub;
+    }
+
+    public stopWatch(key: string, obs: BehaviorSubject<string>){
+        const subs = this.subscribers.get(key);
+        subs.splice(subs.indexOf(obs), 1);
+    };
+}