From 08e3933c4a6b4a4cd511dde945b343a598e5a75a Mon Sep 17 00:00:00 2001
From: Shweelan Samson <shweelan@genieacs.com>
Date: Tue, 2 Apr 2019 20:48:13 +0300
Subject: [PATCH] Support function context in expression's evaluate

---
 lib/common/expression.ts | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/common/expression.ts b/lib/common/expression.ts
index d2611e4..43a934f 100644
--- a/lib/common/expression.ts
+++ b/lib/common/expression.ts
@@ -88,7 +88,10 @@ export function evaluate(exp, obj?, now?: number, cb?: Function): Expression {
     } else if (e[0] === "PARAM") {
       if (e[1] == null) return null;
       if (obj && !isArray(e[1])) {
-        let v = obj[e[1]];
+        let v;
+        if (typeof obj === "function") v = obj(e[1]);
+        else v = obj[e[1]];
+
         if (v == null) return null;
         if (typeof v === "object") v = v.value ? v.value[0] : null;
         return v;