# Quick Question Around Subflow EV's

**URL:** <https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159>\
**Category:** General\
**Tags:** subflow, environment-variable\
**Created:** [21 March 2025 19:00 UTC](https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159 "2025-03-21T19:00:11Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [21 March 2025 19:00 UTC](https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159/1 "2025-03-21T19:00:11Z")

</div>

I tend to add a UI defined Variable for a subflow - ✅  
But inside the subflow, it needs to get updated later (periodically)

So lets call this EV, the "Initial Value" (the label at least, but behind the scenes its called "CurrentValue")

Can I update it internally? if so - is its written to the FS? - My default storage is the FS.

I hope this makes sence

 ![Screenshot 2025-03-21 at 19.00.39](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/3/f/3f109c0cc3d6e2d17c8ee367d1b0ac7c36b7a522.png)

Thank you please!

---

<div class="post-metadata">

**Author:** ![knolleary](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/knolleary/32/3_2.png) [@knolleary](https://discourse.nodered.org/u/knolleary)\
**Post date:** [21 March 2025 21:48 UTC](https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159/2 "2025-03-21T21:48:44Z")

</div>

All env vars are defined in the flow JSON and are only evaluated when the flows start. The only way a value can be changed is by restarting the flows so they get re-evaluated.

---

<div class="post-metadata">

**Author:** ![marcus-j-davies](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/marcus-j-davies/32/103435_2.png) [@marcus-j-davies](https://discourse.nodered.org/u/marcus-j-davies)\
**Post date:** [21 March 2025 21:52 UTC](https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159/3 "2025-03-21T21:52:12Z")

</div>

Thanks Nick.

I guess I need to use logical OR for my needs.  
no problem of course, was just curious if its possible

---

<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:** [4 April 2025 21:52 UTC](https://discourse.nodered.org/t/quick-question-around-subflow-evs/96159/4 "2025-04-04T21:52:31Z")

</div>

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