Add persistantFrontEndValue property to addWidget options so it possbile to avoid replay message to be sent when front end reconnect (#558)

Author: ThierryLeGal

index.js

@@ -32,14 +32,16 @@ function init(RED) {
        * [width] - width of widget (default automatic)
        * [height] - height of widget (default automatic)
        * [order] - property to hold the placement order of the widget (default 0)
-       * [templateScope] - scope of widhget/global or local (default local)
+       * [templateScope] - scope of widget/global or local (default local)
        * [emitOnlyNewValues] - boolean (default true).
              If true, it checks if the payload changed before sending it
              to the front-end. If the payload is the same no message is sent.
        * [forwardInputMessages] - boolean (default true).
              If true, forwards input messages to the output
        * [storeFrontEndInputAsState] - boolean (default true).
              If true, any message received from front-end is stored as state
+        [persistantFrontEndValue] - boolean (default true).
+             If true, last received message is send again when front end reconnect.
        * [convert] - callback to convert the value before sending it to the front-end
        * [beforeEmit] - callback to prepare the message that is emitted to the front-end
        * [convertBack] - callback to convert the message from front-end before sending it to the next connected node
@@ -95,6 +97,9 @@ function addWidget(RED, options) {
     if (options.hasOwnProperty("storeFrontEndInputAsState")) {
         ui_options.storeFrontEndInputAsState = options.storeFrontEndInputAsState;
     }
+    if (options.hasOwnProperty("persistantFrontEndValue")) {
+        ui_options.persistantFrontEndValue  = options.persistantFrontEndValue;
+    }
     if (options.hasOwnProperty("convert")) {
         ui_options.convert = options.convert;
     }

ui.js

@@ -111,6 +111,8 @@ options:
         If true, forwards input messages to the output
     [storeFrontEndInputAsState] - boolean (default true).
         If true, any message received from front-end is stored as state
+    [persistantFrontEndValue] - boolean (default true).
+        If true, last received message is send again when front end reconnect.
 
     [convert] - callback to convert the value before sending it to the front-end
     [beforeEmit] - callback to prepare the message that is emitted to the front-end
@@ -131,6 +133,9 @@ function add(opt) {
     if (typeof opt.storeFrontEndInputAsState === 'undefined') {
         opt.storeFrontEndInputAsState = true;
     }
+    if (typeof opt.persistantFrontEndValue  === 'undefined') {
+        opt.persistantFrontEndValue  = true;
+    }
     opt.convert = opt.convert || noConvert;
     opt.beforeEmit = opt.beforeEmit || beforeEmit;
     opt.convertBack = opt.convertBack || noConvert;
@@ -248,7 +253,9 @@ function add(opt) {
             // Emit and Store the data
             //if (settings.verbose) { console.log("UI-EMIT",JSON.stringify(toEmit)); }
             emitSocket(updateValueEventName, toEmit);
-            replayMessages[opt.node.id] = toStore;
+            if (opt.persistantFrontEndValue) {
+                replayMessages[opt.node.id] = toStore;
+            }
 
             // Handle the node output
             if (opt.forwardInputMessages && opt.node._wireCount) {
@@ -270,7 +277,9 @@ function add(opt) {
             var converted = opt.convertBack(msg.value);
             if (opt.storeFrontEndInputAsState === true) {
                 currentValues[msg.id] = converted;
-                replayMessages[msg.id] = msg;
+                if (opt.persistantFrontEndValue) {
+                    replayMessages[msg.id] = msg;
+                }
             }
             var toSend = {payload:converted};
             toSend = opt.beforeSend(toSend, msg) || toSend;