# Problem add Object to Array

**URL:** <https://discourse.nodered.org/t/problem-add-object-to-array/25763>\
**Category:** General\
**Created:** [29 April 2020 20:24 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763 "2020-04-29T20:24:56Z")\
**Posts on this page:** 7\
**Page:** 1

<div class="post-metadata">

**Author:** ![grooveagent](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@grooveagent](https://discourse.nodered.org/u/grooveagent)\
**Post date:** [29 April 2020 20:24 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/1 "2020-04-29T20:24:56Z")

</div>

Hi together,

I'm stuck with a beginner Problem to push an Object to an Array of Object...

What I want to do:  
I have a dashboard where the user can put in different values which are stored in several object-properties. With every input the whole object is stored in global context variable "tempstore".  
When all inputs are done, I want to push the object to an array of object.  
What happens is, that when I add a new Object to my array, all Object-properties of former array elements get the property-values of the last added array element...what am I doing wrong??

JS-Code to set a property from dashboard. Have it for 3 properties (val1, val2, val3):

```auto
var local = global.get ("tempstore") || {};
local.val1 = msg.payload;
global.set ("tempstore", local);
return msg;

```

Code to save the object to array:

```auto
var local_arr = global.get ("array") || [];
var local_tempstore = global.get ("tempstore") || {};

local_arr[local_arr.length] = local_tempstore;
global.set("array",local_arr);

return msg;

```

when the first Object was  
val1: "value1", val2: 1, val3: 44100000  
and the second Object was  
val1: "value2", val2: 2, val3: 44100000  
the result is...  
 ![image](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/d/d/dd226263eadc12953164be1ffcf80a88e162302b.png)

I hope somebody can help me with this problem - thanks!

---

<div class="post-metadata">

**Author:** ![bakman2](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/bakman2/32/6207_2.png) [@bakman2](https://discourse.nodered.org/u/bakman2)\
**Post date:** [29 April 2020 20:58 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/2 "2020-04-29T20:58:43Z")

</div>

> [@grooveagent](#):
>
> push

Use

```auto
local_arr.push(local_arr)

```

---

<div class="post-metadata">

**Author:** ![Colin](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/colin/32/17040_2.png) [@Colin](https://discourse.nodered.org/u/Colin)\
**Post date:** [30 April 2020 10:12 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/3 "2020-04-30T10:12:37Z")

</div>

The code you have should work I think, though `push` is obviously cleaner. I suspect you may be falling over the fact that objects in javascript are accessed by reference, so it may be that when you setup the two messages that feed into the first function that you are actually passing the same object in the payload. How are you generating those two messages?  
If you don't think that is the problem then can you construct a mini-flow showing the problem and export that here?

---

<div class="post-metadata">

**Author:** ![grooveagent](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@grooveagent](https://discourse.nodered.org/u/grooveagent)\
**Post date:** [30 April 2020 20:27 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/4 "2020-04-30T20:27:00Z")

</div>

Thanks for your replies. I think you are right Colin...I am not really used to call by reference...I did a check with RED.util.cloneMessage...but to be honest...I don't understand why it works now and did not before...

**First question:**  
In some other posts when reading into storing data in context I thought to have understood to first get my element from global storage by storing it in a local variable... var local\_val = global.get("value")...  
Then I thought I have to manipulate the local variable and store it back to context by calling global.set("value", local\_var). But why should I use global.set to store the local value back to context, when manipulating my local\_var already manipulates context because of the command local\_val = global.get("value")....?

**Second question**  
I changed my code als follows and now it works:

Get elements from dashboard and safe it temporarily in context:

```auto
var local = global.get ("tempstore") || {};
local.val1 = msg.payload;
//global.set ("tempstore", local); -> Does not matter, if I use this line or not. 
return msg;

```

Safe temporary variable with the three elements in an array of object in context when clicking on button:

```auto
var local_arr = RED.util.cloneMessage(global.get ("array")) || [];
var local_tempstore = RED.util.cloneMessage(global.get ("tempstore")) || {};

local_arr[local_arr.length] = local_tempstore;
global.set("array",local_arr);

return msg;

```

So when using cloneMessage it works....but why not without it. I thought the line `local_arr[local_arr.length] = local_tempstore;` means that the new array element now points to the adress of local\_tempstore....why should this line also alter older array elements?

**Last question:**  
Is there a more elegant way than I did it to collect data from multiple inputs from dashboard and then store it to context by clicking a button?

Here is my example flow:

```auto
[{"id":"59d61ca8.536c24","type":"tab","label":"arraytest","disabled":false,"info":""},{"id":"37232382.b39d0c","type":"ui_button","z":"59d61ca8.536c24","name":"New array element","group":"6aeb6a04.8ceb74","order":0,"width":0,"height":0,"passthru":false,"label":"New array element","tooltip":"","color":"","bgcolor":"","icon":"","payload":"","payloadType":"str","topic":"","x":170,"y":380,"wires":[["97d2b91a.c48f88"]]},{"id":"b5fe945c.94b5c8","type":"inject","z":"59d61ca8.536c24","name":"Init","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":130,"y":160,"wires":[["7062d938.8c66f8"]]},{"id":"7062d938.8c66f8","type":"function","z":"59d61ca8.536c24","name":"declare vars","func":"var array = [];\nvar tempstore = {val1 : \"\", val2 : \"\", val3 : \"\"};\n\nglobal.set (\"array\", array);\nglobal.set(\"tempstore\", tempstore);\n\n\nreturn msg;","outputs":1,"noerr":0,"x":380,"y":160,"wires":[[]]},{"id":"e2b13d93.e78ea","type":"ui_text_input","z":"59d61ca8.536c24","name":"Value 1","label":"Value 1","tooltip":"","group":"6aeb6a04.8ceb74","order":1,"width":0,"height":0,"passthru":true,"mode":"text","delay":300,"topic":"","x":140,"y":220,"wires":[["f451c7e7.bd8018"]]},{"id":"9bd4073c.45bc38","type":"ui_text_input","z":"59d61ca8.536c24","name":"Value 2","label":"Value 2","tooltip":"","group":"6aeb6a04.8ceb74","order":1,"width":0,"height":0,"passthru":true,"mode":"number","delay":300,"topic":"","x":140,"y":260,"wires":[["7aebbb92.5108c4"]]},{"id":"b5212d75.dbe24","type":"ui_text_input","z":"59d61ca8.536c24","name":"Value 3","label":"Value 3","tooltip":"","group":"6aeb6a04.8ceb74","order":1,"width":0,"height":0,"passthru":true,"mode":"time","delay":300,"topic":"","x":140,"y":300,"wires":[["5cdd891b.6c8828"]]},{"id":"60c671bd.773c8","type":"ui_button","z":"59d61ca8.536c24","name":"Delete array Element","group":"6aeb6a04.8ceb74","order":0,"width":0,"height":0,"passthru":false,"label":"Delete array Element","tooltip":"","color":"","bgcolor":"","icon":"","payload":"","payloadType":"str","topic":"","x":180,"y":420,"wires":[["a118a1ce.aee24"]]},{"id":"f451c7e7.bd8018","type":"function","z":"59d61ca8.536c24","name":"store value","func":"var local = global.get (\"tempstore\") || {};\nlocal.val1 = msg.payload;\n//global.set (\"tempstore\", local);\nreturn msg;","outputs":1,"noerr":0,"x":330,"y":220,"wires":[[]]},{"id":"97d2b91a.c48f88","type":"function","z":"59d61ca8.536c24","name":"new array element","func":"var local_arr = RED.util.cloneMessage(global.get (\"array\")) || [];\nvar local_tempstore = RED.util.cloneMessage(global.get (\"tempstore\")) || {};\n\nlocal_arr[local_arr.length] = local_tempstore;\nglobal.set(\"array\",local_arr);\n\nreturn msg;","outputs":1,"noerr":0,"x":470,"y":380,"wires":[[]]},{"id":"a118a1ce.aee24","type":"function","z":"59d61ca8.536c24","name":"delete array element","func":"var local = global.get (\"array\") || [];\nif (local.length > 0)\n{\n local.splice(0, 1); \n}\n\nreturn msg;","outputs":1,"noerr":0,"x":480,"y":420,"wires":[[]]},{"id":"7aebbb92.5108c4","type":"function","z":"59d61ca8.536c24","name":"store value","func":"var local = global.get (\"tempstore\") || {};\nlocal.val2 = msg.payload;\n//global.set (\"tempstore\", local);\nreturn msg;","outputs":1,"noerr":0,"x":330,"y":260,"wires":[[]]},{"id":"5cdd891b.6c8828","type":"function","z":"59d61ca8.536c24","name":"store value","func":"var local = global.get (\"tempstore\") || {};\nlocal.val3 = msg.payload;\n//global.set (\"tempstore\", local);\nreturn msg;","outputs":1,"noerr":0,"x":330,"y":300,"wires":[[]]},{"id":"6aeb6a04.8ceb74","type":"ui_group","z":"","name":"arraytest1","tab":"65f4b3d5.cbcf4c","disp":false,"width":"6","collapse":false},{"id":"65f4b3d5.cbcf4c","type":"ui_tab","z":"","name":"arraytest","icon":"dashboard","disabled":false,"hidden":false}]

```

Thank you!

---

<div class="post-metadata">

**Author:** ![zenofmud](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/zenofmud/32/316_2.png) [@zenofmud](https://discourse.nodered.org/u/zenofmud)\
**Post date:** [30 April 2020 20:55 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/5 "2020-04-30T20:55:41Z")

</div>

> [@grooveagent](#):
>
> how can I put this into one line?

enter three back tics, then on a new line your code, then three more back tics on another new line. I edited your post so you can see how to do it

---

<div class="post-metadata">

**Author:** ![grooveagent](https://avatars.discourse-cdn.com/v4/letter/g/67e7ee/32.png) [@grooveagent](https://discourse.nodered.org/u/grooveagent)\
**Post date:** [1 May 2020 11:53 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/6 "2020-05-01T11:53:49Z")

</div>

Ok, I got it, sometimes it needs some sleep in between. Every array element points to local\_tempstore and with that to the same adress in global context...

Thanks for your Help!

---

<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:** [15 May 2020 11:53 UTC](https://discourse.nodered.org/t/problem-add-object-to-array/25763/7 "2020-05-15T11:53:54Z")

</div>

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