Allow trigger node to use other than msg.topic to separate streams

and add test

packages/node_modules/@node-red/nodes/core/function/89-trigger.html

@@ -62,10 +62,13 @@
     <br/>
     <div class="form-row">
         <label data-i18n="trigger.for" for="node-input-bytopic"></label>
-        <select id="node-input-bytopic">
+        <select id="node-input-bytopic" style="width:120px;">
             <option value="all" data-i18n="trigger.alltopics"></option>
             <option value="topic" data-i18n="trigger.bytopics"></option>
         </select>
+        <span class="form-row" id="node-trigger-property">
+            <input type="text" id="node-input-property" style="width:46%;"/>
+        </span>
     </div>
     <div class="form-row">
         <label for="node-input-name"><i class="fa fa-tag"></i> <span data-i18n="common.label.name"></span></label>
@@ -78,6 +81,7 @@
         category: 'function',
         color:"#E6E0F8",
         defaults: {
+            name: {value:""},
             op1: {value:"1", validate: RED.validators.typedInput("op1type")},
             op2: {value:"0", validate: RED.validators.typedInput("op2type")},
             op1type: {value:"val"},
@@ -89,7 +93,7 @@
             reset: {value:""},
             bytopic: {value:"all"},
             outputs: {value:1},
-            name: {value:""}
+            property: {value:"topic",required:true}
         },
         inputs:1,
         outputs:1,
@@ -110,6 +114,19 @@
         },
         oneditprepare: function() {
             var that = this;
+            if (this.property === undefined) {
+                $("#node-input-property").val("topic");
+            }
+            $("#node-input-property").typedInput({default:'msg',types:['msg']});
+            $("#node-input-bytopic").on("change", function() {
+                console.log("BYT",$("#node-input-bytopic").val());
+                if ($("#node-input-bytopic").val() === "all") {
+                    $("#node-trigger-property").hide();
+                } else {
+                    $("#node-trigger-property").show();
+                }
+            });
+        
             $("#node-input-second").change(function() {
                 if ($("#node-input-second").is(":checked")) {
                     that.outputs = 2;
@@ -191,8 +208,6 @@
             if ($("#node-then-type").val() == "loop") {
                 $("#node-input-duration").val($("#node-input-duration").val() * -1);
             }
-
-
         }
     });
 </script>

packages/node_modules/@node-red/nodes/core/function/89-trigger.js

@@ -25,6 +25,7 @@ module.exports = function(RED) {
         this.op1type = n.op1type || "str";
         this.op2type = n.op2type || "str";
         this.second = n.second || false;
+        this.property = n.property || "topic";
 
         if (this.op1type === 'val') {
             if (this.op1 === 'true' || this.op1 === 'false') {
@@ -112,7 +113,7 @@ module.exports = function(RED) {
         });
 
         var processMessage = function(msg) {
-            var topic = msg.topic || "_none";
+            var topic = RED.util.getMessageProperty(msg,node.property) || "_none";
             var promise;
             if (node.bytopic === "all") { topic = "_none"; }
             node.topics[topic] = node.topics[topic] || {};