# Ask : two node to one function?

**URL:** <https://discourse.nodered.org/t/ask-two-node-to-one-function/47736>\
**Category:** General\
**Created:** [28 June 2021 08:30 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736 "2021-06-28T08:30:15Z")\
**Posts on this page:** 11\
**Page:** 1

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**Author:** ![jlian168](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jlian168/32/43737_2.png) [@jlian168](https://discourse.nodered.org/u/jlian168)\
**Post date:** [28 June 2021 08:30 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/1 "2021-06-28T08:30:16Z")

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Dear All :

1. The switch has topic is no2\_pn, but hv error...why?
2. In the code Line 20 that is correct?
3. Or in the code has another error?

Thank u.

 ![螢幕擷取畫面 2021-06-28 162524](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/3X/f/9/f922c8e706cc669306bf9e8e346d80902e7d4554.jpeg)

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**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:** [28 June 2021 08:38 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/2 "2021-06-28T08:38:38Z")

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The error is because `no2_pn` is a String value so it needs to have `"` around it. The same is true for `"no2_cali_val"` and `"no2_array"`.

```auto
if (msg.topic == "no2_pn")

```

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<div class="post-metadata">

**Author:** ![jlian168](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jlian168/32/43737_2.png) [@jlian168](https://discourse.nodered.org/u/jlian168)\
**Post date:** [28 June 2021 08:51 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/3 "2021-06-28T08:51:37Z")

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Dear Sir :

I hope the output is no2\_array, not "no2\_array".  
So how to do?

Thank u.

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<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:** [28 June 2021 08:53 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/4 "2021-06-28T08:53:09Z")

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I'm sorry - I did not spot that `no2_array` was a locally defined variable.

So `"no2_pn"` and `"no2_cali_val"` are String types and need quotes.

`no2_array` is a local variable so does _not_ need quotes.

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**Author:** ![jlian168](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jlian168/32/43737_2.png) [@jlian168](https://discourse.nodered.org/u/jlian168)\
**Post date:** [28 June 2021 08:56 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/5 "2021-06-28T08:56:30Z")

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Dear Sir :

Thank u.

1. But if no "no2\_array" that it still has error...
2. How can I output value that is no2\_array's vaule.
3. Cause the value is numberic.

Thanks again.

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<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:** [28 June 2021 08:58 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/6 "2021-06-28T08:58:24Z")

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Please share your code (not a screenshot, paste it in and format it as a code block using by wrapping it with ```.

What error are you now getting?

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<div class="post-metadata">

**Author:** ![jlian168](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jlian168/32/43737_2.png) [@jlian168](https://discourse.nodered.org/u/jlian168)\
**Post date:** [28 June 2021 09:02 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/7 "2021-06-28T09:02:04Z")

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Dear Sir :

1. The code is below:

```auto
//var i;
//var j;
var no2_array=[];
if(msg.topic=="no2_pn") 
{
    if(msg.payload==true)
        no2_array[0]=0; //+
    else
        no2_array[0]=1; //-
    
}
//
if(msg.topic=="no2_cali_val")
{
    //1j=msg.payload;
    no2_array[1]=(msg.payload<<8);
    no2_array[2]=msg.payload&0xFF;
}
//
msg.payload="no2_array";
return msg;

```

1. So msg.payload's value is always string?

Thank u.

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<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [28 June 2021 09:21 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/8 "2021-06-28T09:21:36Z")

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I have edited your last post, but next time that you post any code, please use three back ticks and not quotations.  
Like this ```  
and not """

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<div class="post-metadata">

**Author:** ![Paul-Reed](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/paul-reed/32/66906_2.png) [@Paul-Reed](https://discourse.nodered.org/u/Paul-Reed)\
**Post date:** [28 June 2021 09:25 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/9 "2021-06-28T09:25:46Z")

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> [@jlian168](#):
>
> So msg.payload's value is always string?

No, `no2_array` is a variable and not a string, so you don't need string quotes around it.  
So instead of `msg.payload="no2_array";` you need `msg.payload=no2_array;`

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<div class="post-metadata">

**Author:** ![jlian168](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/jlian168/32/43737_2.png) [@jlian168](https://discourse.nodered.org/u/jlian168)\
**Post date:** [28 June 2021 09:36 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/10 "2021-06-28T09:36:23Z")

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Dear Sir :

1. I will use ''' next time.
2. its right : msg.payload=no2\_array;

Thank u.

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**Author:** ![system](https://us1.discourse-cdn.com/flex026/uploads/nodered/original/1X/d073cd938eafa2e558d7c2cd59003b3ef4963033.png) [@system](https://discourse.nodered.org/u/system)\
**Post date:** [27 August 2021 09:37 UTC](https://discourse.nodered.org/t/ask-two-node-to-one-function/47736/11 "2021-08-27T09:37:01Z")

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