# How check context exist

**URL:** <https://discourse.nodered.org/t/how-check-context-exist/24515>\
**Category:** General\
**Created:** [9 April 2020 10:38 UTC](https://discourse.nodered.org/t/how-check-context-exist/24515 "2020-04-09T10:38:21Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![d0d04m3](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/d0d04m3/32/19965_2.png) [@d0d04m3](https://discourse.nodered.org/u/d0d04m3)\
**Post date:** [9 April 2020 10:38 UTC](https://discourse.nodered.org/t/how-check-context-exist/24515/1 "2020-04-09T10:38:21Z")

</div>

hi  
I receive data but before updated I need check if data it's same or this object if exist or not  
so if exist check is data if equal else update  
or if not exist save it  
example check object "V06-bus" exist or not  
how that  
 ![context](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/1/d1000c3f504537a0694ce06d7582a0a8c6503fb9.png)

---

<div class="post-metadata">

**Author:** ![hotNipi](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/hotnipi/32/383_2.png) [@hotNipi](https://discourse.nodered.org/u/hotNipi)\
**Post date:** [9 April 2020 10:48 UTC](https://discourse.nodered.org/t/how-check-context-exist/24515/2 "2020-04-09T10:48:38Z")

</div>

With function node most simple case may be something like this

```auto
var stored = flow.get("stored")
// if stored object has not created yet, it is undefined
node.warn("check "+stored)
if(stored != msg.payload){
    // incoming data is not same as stored data
    node.warn("stroing "+msg.payload)   
    flow.set("stored", msg.payload)
}

```

---

<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [23 April 2020 10:48 UTC](https://discourse.nodered.org/t/how-check-context-exist/24515/3 "2020-04-23T10:48:43Z")

</div>

This topic was automatically closed 14 days after the last reply. New replies are no longer allowed.