# Subtract 5minuts from a time out of a state node

**URL:** <https://discourse.nodered.org/t/subtract-5minuts-from-a-time-out-of-a-state-node/42122>\
**Category:** General\
**Created:** [5 March 2021 21:19 UTC](https://discourse.nodered.org/t/subtract-5minuts-from-a-time-out-of-a-state-node/42122 "2021-03-05T21:19:47Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![MarkV](https://avatars.discourse-cdn.com/v4/letter/m/8edcca/32.png) [@MarkV](https://discourse.nodered.org/u/MarkV)\
**Post date:** [5 March 2021 21:19 UTC](https://discourse.nodered.org/t/subtract-5minuts-from-a-time-out-of-a-state-node/42122/1 "2021-03-05T21:19:48Z")

</div>

Hello,

This is my first post on this forum. I'm rather new to nodered and looked at severall youtube tutorials, but can't find the answer on my problem.

I'm creating a flow in what has to do the following:

- When i change my alarm on my mobile it has to get the wakeup time;
- After this it has to subtract 5minuts of the set time;
- On the time minus 5minuts i want to have my lights go on, on 40%;
- On the set time the lights go brighter on 70%.

I catch the new alarm time with a state node, and it looks like:

```auto
{"topic":"sensor.sm_g920f_volgende_alarm","payload":"2021-03-06T04:10:00.000Z","data":{"entity_id":"sensor.sm_g920f_volgende_alarm","old_state":{"entity_id":"sensor.sm_g920f_volgende_alarm","state":"unknown","attributes":{"friendly_name":"SM-G920F Volgende alarm","icon":"mdi:alarm","device_class":"timestamp"},"last_changed":"2021-03-05T18:51:55.255378+00:00","last_updated":"2021-03-05T18:51:55.255378+00:00","context":{"id":"b47d7b96fae6d771440480089578579a","parent_id":null,"user_id":null},"original_state":"unknown"},"new_state":{"entity_id":"sensor.sm_g920f_volgende_alarm","state":"2021-03-06T04:10:00.000Z","attributes":{"Local Time":"Sat Mar 06 05:10:00 GMT+01:00 2021","Package":"com.sec.android.app.clockpackage","Time in Milliseconds":1615003800000,"friendly_name":"SM-G920F Volgende alarm","icon":"mdi:alarm","device_class":"timestamp"},"last_changed":"2021-03-05T21:12:38.733236+00:00","last_updated":"2021-03-05T21:12:38.733236+00:00","context":{"id":"4791f4daa44c22405ea6143da5e9e78c","parent_id":null,"user_id":null},"original_state":"2021-03-06T04:10:00.000Z","timeSinceChangedMs":16}},"_msgid":"6b4035b8.08086c"}

```

How can i use the newly set time ("attributes":{"Local Time":"Sat Mar 06 05:10:00 GMT+01:00 2021") and subtract the 5 minuts of of it, to turn the light on on the subtracted time?  
Hoping someone could give me some plain and simpel examples.

Thanks in advance

---

<div class="post-metadata">

**Author:** ![Steve-Mcl](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/steve-mcl/32/4826_2.png) [@Steve-Mcl](https://discourse.nodered.org/u/Steve-Mcl)\
**Post date:** [6 March 2021 12:04 UTC](https://discourse.nodered.org/t/subtract-5minuts-from-a-time-out-of-a-state-node/42122/2 "2021-03-06T12:04:32Z")

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> [@MarkV](#):
>
> How can i use the newly set time ("attributes":{"Local Time":"Sat Mar 06 05:10:00 GMT+01:00 2021") and subtract the 5 minuts of of it

Here is a demo showing you how to mess about with date/time in JavaScript (look in the function node)...

![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/8/7/87494292a171bc5e9f3fbcd4abfc75b3e305d460.png)

the flow...

```auto
[{"id":"2ae8a960.ed9c36","type":"inject","z":"2680e2cc.e6dace","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"topic\":\"sensor.sm_g920f_volgende_alarm\",\"payload\":\"2021-03-06T04:10:00.000Z\",\"data\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"old_state\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"state\":\"unknown\",\"attributes\":{\"friendly_name\":\"SM-G920F Volgende alarm\",\"icon\":\"mdi:alarm\",\"device_class\":\"timestamp\"},\"last_changed\":\"2021-03-05T18:51:55.255378+00:00\",\"last_updated\":\"2021-03-05T18:51:55.255378+00:00\",\"context\":{\"id\":\"b47d7b96fae6d771440480089578579a\",\"parent_id\":null,\"user_id\":null},\"original_state\":\"unknown\"},\"new_state\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"state\":\"2021-03-06T04:10:00.000Z\",\"attributes\":{\"Local Time\":\"Sat Mar 06 05:10:00 GMT+01:00 2021\",\"Package\":\"com.sec.android.app.clockpackage\",\"Time in Milliseconds\":1615003800000,\"friendly_name\":\"SM-G920F Volgende alarm\",\"icon\":\"mdi:alarm\",\"device_class\":\"timestamp\"},\"last_changed\":\"2021-03-05T21:12:38.733236+00:00\",\"last_updated\":\"2021-03-05T21:12:38.733236+00:00\",\"context\":{\"id\":\"4791f4daa44c22405ea6143da5e9e78c\",\"parent_id\":null,\"user_id\":null},\"original_state\":\"2021-03-06T04:10:00.000Z\",\"timeSinceChangedMs\":16}},\"_msgid\":\"6b4035b8.08086c\"}","payloadType":"json","x":690,"y":620,"wires":[["fdbcdff.c59dc2"]]},{"id":"fdbcdff.c59dc2","type":"function","z":"2680e2cc.e6dace","name":"","func":"//msg.payload\nvar fiveMinsAsMS = (60*1000)*5;\nvar AlarmSetLocalTimeStr = msg.payload.data.new_state.attributes[\"Local Time\"];\nvar alarmSetTimeMS = msg.payload.data.new_state.attributes[\"Time in Milliseconds\"];\nvar alarmSetTimeDT = new Date(alarmSetTimeMS)\nvar alarmSetTimeLess5mMS = alarmSetTimeMS - fiveMinsAsMS;\nvar alarmSetTimeLess5mDT = new Date(alarmSetTimeLess5mMS);\nvar alarmSetTimeLess5mLocal = alarmSetTimeLess5mDT.toString();\nvar alarmSetTimeLess5mLocale = alarmSetTimeLess5mDT.toLocaleString(\"en-GB\", { timeZone: 'UTC' });\n\nmsg.payload = {\n AlarmSetLocalTimeStr: AlarmSetLocalTimeStr,\n AlarmSetTimeMS: alarmSetTimeMS,\n alarmSetTimeDT: alarmSetTimeDT,\n alarmSetTimeLess5mMS: alarmSetTimeLess5mMS,\n alarmSetTimeLess5mDT: alarmSetTimeLess5mDT,\n alarmSetTimeLess5mLocale: alarmSetTimeLess5mLocale\n}\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":840,"y":620,"wires":[["f598d951.3b3d88"]]},{"id":"f598d951.3b3d88","type":"debug","z":"2680e2cc.e6dace","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":1030,"y":620,"wires":[]}]

```

  

> [@MarkV](#):
>
> to turn the light on on the subtracted time

You could do this a number of ways. Here is a demo using cron-plus. It takes the datetime in your data, minuses 5m, prepares a command to add/update a dynamic schedule in the cron-plus node...

 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/c/5/c53bbca1f0f8a6ec33487b3d7846ee98dd1c666a.png)  
↑ NOTE I had to overwrite the datetime from your sample alarm data as it was in the past (and the cron node cannot time travel) 😉

the flow...

```auto
[{"id":"9631a70f.fa3998","type":"cronplus","z":"275d89c3.163556","name":"","outputField":"payload","timeZone":"","persistDynamic":false,"commandResponseMsgOutput":"output1","outputs":1,"options":[],"x":1400,"y":600,"wires":[["42c23eb7.6f6be"]]},{"id":"1f3cd0a4.6dd34f","type":"inject","z":"275d89c3.163556","name":"sm_g920f_volgende_alarm (fake)","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"{\"topic\":\"sensor.sm_g920f_volgende_alarm\",\"payload\":\"2021-03-06T04:10:00.000Z\",\"data\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"old_state\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"state\":\"unknown\",\"attributes\":{\"friendly_name\":\"SM-G920F Volgende alarm\",\"icon\":\"mdi:alarm\",\"device_class\":\"timestamp\"},\"last_changed\":\"2021-03-05T18:51:55.255378+00:00\",\"last_updated\":\"2021-03-05T18:51:55.255378+00:00\",\"context\":{\"id\":\"b47d7b96fae6d771440480089578579a\",\"parent_id\":null,\"user_id\":null},\"original_state\":\"unknown\"},\"new_state\":{\"entity_id\":\"sensor.sm_g920f_volgende_alarm\",\"state\":\"2021-03-06T04:10:00.000Z\",\"attributes\":{\"Local Time\":\"Sat Mar 06 05:10:00 GMT+01:00 2021\",\"Package\":\"com.sec.android.app.clockpackage\",\"Time in Milliseconds\":1615003800000,\"friendly_name\":\"SM-G920F Volgende alarm\",\"icon\":\"mdi:alarm\",\"device_class\":\"timestamp\"},\"last_changed\":\"2021-03-05T21:12:38.733236+00:00\",\"last_updated\":\"2021-03-05T21:12:38.733236+00:00\",\"context\":{\"id\":\"4791f4daa44c22405ea6143da5e9e78c\",\"parent_id\":null,\"user_id\":null},\"original_state\":\"2021-03-06T04:10:00.000Z\",\"timeSinceChangedMs\":16}},\"_msgid\":\"6b4035b8.08086c\"}","payloadType":"json","x":1390,"y":480,"wires":[["875aa68.212fa58"]]},{"id":"875aa68.212fa58","type":"function","z":"275d89c3.163556","name":"Minus 5m and prepare cron command","func":"//msg.payload\nvar fiveMinsAsMS = (60*1000)*5;\nvar AlarmSetLocalTimeStr = msg.payload.data.new_state.attributes[\"Local Time\"];\nvar alarmSetTimeMS = msg.payload.data.new_state.attributes[\"Time in Milliseconds\"];\n\n//temporary override to demonstrate dynamic cron setting\nalarmSetTimeMS = Date.now() + (60*1000)*10\n\nvar alarmSetTimeDT = new Date(alarmSetTimeMS)\nvar alarmSetTimeLess5mMS = alarmSetTimeMS - fiveMinsAsMS;\nvar alarmSetTimeLess5mDT = new Date(alarmSetTimeLess5mMS);\nvar alarmSetTimeLess5mLocal = alarmSetTimeLess5mDT.toString();\nvar alarmSetTimeLess5mLocale = alarmSetTimeLess5mDT.toLocaleString(\"en-GB\", { timeZone: 'UTC' });\n\n\n\n\nmsg.payload = {\n \"command\": \"add\",\n \"name\": \"alarm\",\n \"expression\": alarmSetTimeLess5mDT,\n \"expressionType\": \"dates\",\n \"payloadType\": \"json\",\n \"payload\": {\n AlarmSetLocalTimeStr: AlarmSetLocalTimeStr,\n AlarmSetTimeMS: alarmSetTimeMS,\n alarmSetTimeDT: alarmSetTimeDT,\n alarmSetTimeLess5mMS: alarmSetTimeLess5mMS,\n alarmSetTimeLess5mDT: alarmSetTimeLess5mDT,\n alarmSetTimeLess5mLocale: alarmSetTimeLess5mLocale\n }\n}\n\n\nreturn msg;","outputs":1,"noerr":0,"initialize":"","finalize":"","x":1410,"y":540,"wires":[["1ffcc612.4b721a","9631a70f.fa3998"]]},{"id":"1ffcc612.4b721a","type":"debug","z":"275d89c3.163556","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":1670,"y":540,"wires":[]},{"id":"42c23eb7.6f6be","type":"debug","z":"275d89c3.163556","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"payload","targetType":"msg","x":1670,"y":600,"wires":[]}]

```

---

<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:** [5 May 2021 12:05 UTC](https://discourse.nodered.org/t/subtract-5minuts-from-a-time-out-of-a-state-node/42122/3 "2021-05-05T12:05:19Z")

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