fix concurrency bug in ~>

Author: andrew-coleman

src/jsonata.js

@@ -1158,13 +1158,11 @@ var jsonata = (function() {
         var result;
 
 
+        var lhs = yield * evaluate(expr.lhs, input, environment);
         if(expr.rhs.type === 'function') {
             // this is a function _invocation_; invoke it with lhs expression as the first argument
-            expr.rhs.arguments.unshift(expr.lhs);
-            result = yield * evaluateFunction(expr.rhs, input, environment);
-            expr.rhs.arguments.shift();
+            result = yield * evaluateFunction(expr.rhs, input, environment, { context: lhs });
         } else {
-            var lhs = yield * evaluate(expr.lhs, input, environment);
             var func = yield * evaluate(expr.rhs, input, environment);
 
             if(!isFunction(func)) {
@@ -1197,7 +1195,7 @@ var jsonata = (function() {
      * @param {Object} environment - Environment
      * @returns {*} Evaluated input data
      */
-    function* evaluateFunction(expr, input, environment) {
+    function* evaluateFunction(expr, input, environment, applyto) {
         var result;
 
         // create the procedure
@@ -1217,6 +1215,9 @@ var jsonata = (function() {
         }
 
         var evaluatedArgs = [];
+        if(typeof applyto !== 'undefined') {
+            evaluatedArgs.push(applyto.context);
+        }
         // eager evaluation - evaluate the arguments
         for (var jj = 0; jj < expr.arguments.length; jj++) {
             const arg = yield* evaluate(expr.arguments[jj], input, environment);

test/async-function.js

@@ -91,6 +91,29 @@ describe('Invoke JSONata with callback - return values', function() {
     });
 });
 
+describe('Evaluate concurrent expressions with callbacks', function() {
+    it('should process two expressions concurrently', function(done) {
+        const expr = jsonata("{'1':'goat','2': 'cheese'} ~> $lookup($string(payload))");
+
+        var count = 0;
+        var partDone = function() {
+            count++;
+            if(count >= 2) {
+                done();
+            }
+        };
+
+        expr.evaluate({"payload":1}, {}, function(err,result) {
+            expect(result).to.equal('goat');
+            partDone();
+        });
+        expr.evaluate({"payload":2}, {}, function(err,result) {
+            expect(result).to.equal('cheese');
+            partDone();
+        });
+    });
+});
+
 describe('Handle chained functions that end in promises', function() {
 
     var counter = function(count) {