Update smqrpc.js

Author: RTL

SMQ-examples/RPC/smqrpc.js

@@ -2,43 +2,51 @@
 function createSmqRpc(smq) {
     let idCounter=0;
     let callbacks={} // saved RPC callbacks: key=id, val=promise
-    smq.subscribe("self", "$RpcResp", {datatype:"json",onmsg:(pl) => {
-        let promise=callbacks[pl.id];
-        if(promise) {
-            delete callbacks[pl.id]; // Release
-            if(pl.err) promise.reject(new Error(pl.err));
-            else promise.resolve(pl.rsp);
-        }
-        else {
-            console.error(`SMQ RPC: promise (callback) not found for id '${pl.id}'`);
-        }
-    }});
+    let subscribed=false;
+    function subscribe() {
+	smq.subscribe("self", "$RpcResp", {datatype:"json",onmsg:(pl) => {
+	    let promise=callbacks[pl.id];
+	    if(promise) {
+		delete callbacks[pl.id]; // Release
+		if(pl.err) promise.reject(new Error(pl.err));
+		else promise.resolve(pl.rsp);
+	    }
+	    else {
+		console.error(`SMQ RPC: promise (callback) not found for id '${pl.id}'`);
+	    }
+	}});
+    };
     return {
-        proxy: new Proxy({}, {
-            get(target, prop, receiver) {
-                // Return a function that, when called, returns a Promise
-                return (...args) => {
-                    return new Promise((resolve, reject) => {
-                        // Assemble payload
-                        const pl = {
-                            id: ++idCounter,
-                            name: prop,
-                            args: args
-                        };
-                        callbacks[idCounter]={resolve:resolve,reject:reject};
-                        smq.pubjson(pl, 1, "$RpcReq"); // Publish to etid 1, the server.
-                    });
-                };
-            }
-        }),
-        disconnect: function(report) {
-            if(false != report) {
-                for(let id in callbacks) {
-                    let promise=callbacks[id];
-                    promise.reject("disconnected");
-                }
-            }
-            callbacks={};
-        }
+	proxy: new Proxy({}, {
+	    get(target, prop, receiver) {
+		// Return a function that, when called, returns a Promise
+		if( ! subscribed ) {
+		    subscribe();
+		    subscribed=true;
+		};
+		return (...args) => {
+		    return new Promise((resolve, reject) => {
+			// Assemble payload
+			const pl = {
+			    id: ++idCounter,
+			    name: prop,
+			    args: args
+			};
+			callbacks[idCounter]={resolve:resolve,reject:reject};
+			smq.pubjson(pl, 1, "$RpcReq"); // Publish to etid 1, the server.
+		    });
+		};
+	    }
+	}),
+	disconnect: function(report) {
+	    if(false != report) {
+		for(let id in callbacks) {
+		    let promise=callbacks[id];
+		    promise.reject("disconnected");
+		}
+	    }
+	    callbacks={};
+	    subscribed=false;
+	}
     };
 };