Add JSONata expr tester and improved feedback

red/api/locales/en-US/editor.json

@@ -398,9 +398,15 @@
     "expressionEditor": {
         "functions": "Functions",
         "insert": "Insert",
-        "title": "JSONata Expression editor"
+        "title": "JSONata Expression editor",
+        "data": "Example message",
+        "result": "Result",
+        "format": "format expression",
+        "compatMode": "Compatibility mode enabled",
+        "compatModeDesc": "<h3>JSONata compatibility mode</h3><p> The current expression appears to still reference <code>msg</code> so will be evaluated in compatibility mode. Please update the expression to not use <code>msg</code> as this mode will be removed in the future.</p><p> When JSONata support was first added to Node-RED, it required the expression to reference the <code>msg</code> object. For example <code>msg.payload</code> would be used to access the payload.</p><p> That is no longer necessary as the expression will be evaluated against the message directly. To access the payload, the expression should be just <code>payload</code>.</p>"
     },
     "jsonEditor": {
-        "title": "JSON editor"
+        "title": "JSON editor",
+        "format": "format JSON"
     }
 }

red/api/locales/en-US/jsonata.json

@@ -110,16 +110,11 @@
         "args": "object",
         "desc": "Splits an object containing key/value pairs into an array of objects, each of which has a single key/value pair from the input object. If the parameter is an array of objects, then the resultant array contains an object for every key/value pair in every object in the supplied array."
     },
-
-    "$context": {
-        "args": "string",
-        "desc": "Retrieves a node context property."
-    },
-    "$flow": {
+    "$flowContext": {
         "args": "string",
         "desc": "Retrieves a flow context property."
     },
-    "$global": {
+    "$globalContext": {
         "args": "string",
         "desc": "Retrieves a global context property."
     }

red/runtime/util.js

@@ -323,25 +323,33 @@ function evaluateNodeProperty(value, type, node, msg) {
     } else if (type === 'bool') {
         return /^true$/i.test(value);
     } else if (type === 'jsonata') {
-        return prepareJSONataExpression(value,node).evaluate({msg:msg});
+        var expr = prepareJSONataExpression(value,node);
+        return evaluateJSONataExpression(expr,msg);
     }
     return value;
 }
 
 function prepareJSONataExpression(value,node) {
     var expr = jsonata(value);
-    expr.assign('context',function(val) {
-        return node.context().get(val);
-    });
-    expr.assign('flow',function(val) {
+    expr.assign('flowContext',function(val) {
         return node.context().flow.get(val);
     });
-    expr.assign('global',function(val) {
+    expr.assign('globalContext',function(val) {
         return node.context().global(val);
     });
+    expr._legacyMode = /(^|[^a-zA-Z0-9_'"])msg([^a-zA-Z0-9_'"]|$)/.test(value);
     return expr;
 }
 
+function evaluateJSONataExpression(expr,msg) {
+    var context = msg;
+    if (expr._legacyMode) {
+        context = {msg:msg};
+    }
+    return expr.evaluate(context);
+}
+
+
 function normaliseNodeTypeName(name) {
     var result = name.replace(/[^a-zA-Z0-9]/g, " ");
     result = result.trim();
@@ -366,5 +374,6 @@ module.exports = {
     evaluateNodeProperty: evaluateNodeProperty,
     normalisePropertyExpression: normalisePropertyExpression,
     normaliseNodeTypeName: normaliseNodeTypeName,
-    prepareJSONataExpression: prepareJSONataExpression
+    prepareJSONataExpression: prepareJSONataExpression,
+    evaluateJSONataExpression: evaluateJSONataExpression
 };