feat: separate json transformation from websocket store

fixes #539

BREAKING CHANGE: websocketStore transparently passes values (strings). JSON encoding/decoding must be handeled separatly

src/index.mjs

@@ -2,7 +2,6 @@ const reopenTimeouts = [2000, 5000, 10000, 30000, 60000];
 
 /**
  * Create a writable store based on a web-socket.
- * Data is transferred as JSON.
  * Keeps socket open (reopens if closed) as long as there are subscriptions.
  * @param {string} url the WebSocket url
  * @param {any} initialValue store value used before 1st. response from server is present
@@ -54,7 +53,7 @@ export function websocketStore(url, initialValue, socketOptions) {
     socket = new WebSocket(url, socketOptions);
 
     socket.onmessage = event => {
-      initialValue = JSON.parse(event.data);
+      initialValue = event.data;
       subscriptions.forEach(subscription => subscription(initialValue));
     };
 
@@ -76,7 +75,7 @@ export function websocketStore(url, initialValue, socketOptions) {
 
   return {
     set(value) {
-      const send = () => socket.send(JSON.stringify(value));
+      const send = () => socket.send(value);
       if (socket.readyState !== WebSocket.OPEN) open().then(send);
       else send();
     },
@@ -94,4 +93,27 @@ export function websocketStore(url, initialValue, socketOptions) {
   };
 }
 
-export default websocketStore;
+export default websocketStore;
+
+
+export function jsonTransformerStore(store) {
+
+  let subscription = store.subscribe(this);
+
+  //JSON.parse();
+
+  return {
+    set(value) {
+      store.set(JSON.stringify(value));
+    },
+    subscribe(subscription) {
+      subscriptions.add(subscription);
+
+      subscriptions.forEach(subscription => subscription(initialValue));
+
+      return () => {
+        subscriptions.delete(subscription);
+      };
+    }
+  };
+}