# Multiple outputs of function node not working

**URL:** <https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988>\
**Category:** General\
**Created:** [4 August 2019 09:44 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988 "2019-08-04T09:44:30Z")\
**Posts on this page:** 20\
**Page:** 1

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 09:44 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/1 "2019-08-04T09:44:30Z")

</div>

I've read my notes on how to construct nodes with multiple outputs, but it isn't working.

The idea is that the input cycles from 0 to 3 (numbers).  
Depending on its value, depends which output is sent a `1`.  
All values are set to `0` at the beginning and depending on the payload's value, it sets that message's value to `1`.

Ok, the number of `=` signs may be a problem, but I did it with only two and got the same results.

I am getting a lot of `undefined` from the `node.warn( )`  
Yet, they are defined at the top.

So I'm missing something.

Sorry but I can't nut it out.

```auto
var msg1 = 0;
var msg2 = 0;
var msg3 = 0;
var msg4 = 0;
msg.payload = parseInt(msg.payload);
node.warn("message payload is " + msg.payload);
if (msg.payload === 0)
{
    //
    msg1.payload = 1;
} else
if (msg.payload === 1)
{
    //
    msg2.payload = 1;
} else
if (msg.payload === 2)
{
    //
    msg3.payload = 1;
} else
if (msg.payload === 3)
{
    //
    msg4.payload = 1;
}
node.warn("--------");
node.warn(msg1.payload);
node.warn(msg2.payload);
node.warn(msg3.payload);
node.warn(msg4.payload);
return [msg1, msg2, msg3, msg4];

```

---

<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:** [4 August 2019 09:53 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/2 "2019-08-04T09:53:31Z")

</div>

You get undefined because you don't define `msgx.payload` but `msgx = 0`.

try this instead:

```auto
[{"id":"588e975f.2bf15","type":"inject","z":"681f8bde.8887bc","name":"","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":150,"y":450,"wires":[["541beb20.ef86e4"]]},{"id":"541beb20.ef86e4","type":"function","z":"681f8bde.8887bc","name":"","func":"a =2\np = parseInt(msg.payload);\nnode.warn(\"message payload is \" + msg.payload);\n\nout = []\n\nfor(x=0;x<4;x++){\n\t\n\tif(x==a){\n\t\tout.push({payload:p,output:x})\n\t}\n\telse{\n\t\tout.push({payload:null,output:x})\n\n\t}\n}\n\nreturn out","outputs":4,"noerr":0,"x":300,"y":450,"wires":[["f7603811.8dce98"],["87bd304.4a77fd"],["1a51dec4.023271"],["6ce0f346.c1b394"]]},{"id":"f7603811.8dce98","type":"debug","z":"681f8bde.8887bc","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":475,"y":375,"wires":[]},{"id":"87bd304.4a77fd","type":"debug","z":"681f8bde.8887bc","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":475,"y":425,"wires":[]},{"id":"1a51dec4.023271","type":"debug","z":"681f8bde.8887bc","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":475,"y":475,"wires":[]},{"id":"6ce0f346.c1b394","type":"debug","z":"681f8bde.8887bc","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"true","targetType":"full","x":475,"y":525,"wires":[]}]

```

---

<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:** [4 August 2019 09:58 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/3 "2019-08-04T09:58:18Z")

</div>

> [@Trying\_to\_learn](#):
>
> var msg1 = 0; var msg2 = 0; var msg3 = 0; var msg4 = 0;

Change to

```auto
var msg1 = {}; 
var msg2 = {}; 
var msg3 = {}; 
var msg4 = {};

```

---

<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:** [4 August 2019 09:59 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/4 "2019-08-04T09:59:36Z")

</div>

That would still end up as undefined depending on the test.

---

<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:** [4 August 2019 10:00 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/5 "2019-08-04T10:00:57Z")

</div>

Agreed but if one of his tests do pass he'll get an error trying to set/access a property of a non object.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 10:05 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/6 "2019-08-04T10:05:19Z")

</div>

Bakman2

I am not getting (understanding) the code in the `function` node.

I thought (yes: dangerous) that you had to assign variable names.

So, how does:

```auto
a =2
p = parseInt(msg.payload);

```

work?

Shouldn't it be:

```auto
var a = 2;
var p = parseInt(msg.payload);

```

Depending if ....

```auto
p = parseInt(msg.payload);
if (p == 0)
{
    set msg1 to 1
}

```

and so on.

---

<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:** [4 August 2019 10:08 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/7 "2019-08-04T10:08:25Z")

</div>

It could be `var` or `let` or even `const` if they don't get changed, but I'm lazy and it works too.

`msg.payload` is a timestamp and which never be `0` or `1` so that test will fail = no output.  
my example is a bad example 😉 that is why i introduced the `a`, you can replace it ofcourse.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 10:10 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/8 "2019-08-04T10:10:25Z")

</div>

> [@bakman2](#):
>
> It could be `var` or `let` or even `const` if they don't get changed, but I'm lazy and it works too.

Fair enough.

I can't use `const` as they are all set to `0` at the start.  
Depending on the value the appropriate msg_x_ is set to `1`.

> [@bakman2](#):
>
> that is why i introduced the `a` , you can replace it ofcourse.

Um.... Sorry. I get that you introduced the variable `a`, but I am not seeing how that fits in to the workings.

---

<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:** [4 August 2019 10:11 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/9 "2019-08-04T10:11:38Z")

</div>

If you're only wanting to fire a single output, I'd do it like this...

```auto
var p = parseInt(msg.payload);
if (p === 0) {
  return [msg, null, null, null];
} else if (p === 1) {
  return [null, msg, null, null];
} else if (p === 2){
  return [null, null, msg, null];
} else if (p === 3) {
    return [null, null, null, msg];
};

```

but in this case, you could simply use a switch node with 4 == checks

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 10:16 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/10 "2019-08-04T10:16:20Z")

</div>

Thanks Steve.

Close.

The output is only a `1`. Not the actual value.  
The flow is a bit academic as I am using it to test another part.  
This is basically hardware simulation.  
The outputs 0 and 1 are basically `off` and `on`.  
But I get what you wrote.  
So I could change that code to something like:

```auto
var p = parseInt(msg.payload);
if (p === 0) {
  return [1,0,0,0l];
} else if (p === 1) {
  return [0,1,0,0];
} else if (p === 2){
  return [0,0,1,0];
} else if (p === 3) {
    return [0,0,0,1];
};

```

Sure.

I just got confused when I tried to use variables rather than how you did it.

Shall apply your suggestion.

Thanks.

Oh, quickie:  
Why the

```auto
p = parsInt(msg.payload)

```

line?

Wouldn't the line I had work?

```auto
msg.payload = parseInt(msg.payload);

```

---

<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:** [4 August 2019 10:18 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/11 "2019-08-04T10:18:16Z")

</div>

> [@Trying\_to\_learn](#):
>
> var p = parseInt(msg.payload); if (p === 0) { return [1,0,0,0l]; } else if (p === 1) { return [0,1,0,0]; } else if (p === 2){ return [0,0,1,0]; } else if (p === 3) { return [0,0,0,1]; };

That won't work. You MUST return an object...

```auto
var p = parseInt(msg.payload);
msg.payload = 1;
if (p === 0) {
  return [msg, null, null, null];
} else if (p === 1) {
  return [null, msg, null, null];
} else if (p === 2){
  return [null, null, msg, null];
} else if (p === 3) {
    return [null, null, null, msg];
};

```

Will send 1 in payload

---

<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:** [4 August 2019 10:20 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/12 "2019-08-04T10:20:29Z")

</div>

> [@Trying\_to\_learn](#):
>
> Oh, quickie:  
> Why the
> 
> ```auto
> p = parsInt(msg.payload)
> 
> ```
> 
> line?
> 
> Wouldn't the line I had work?
> 
> ```auto
> msg.payload = parseInt(msg.payload);
> 
> ```

So that is more readable and portable and also, as you need to assign 1 to msg.payload before returning.

---

<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:** [4 August 2019 10:24 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/13 "2019-08-04T10:24:14Z")

</div>

The key for multiple outputs is to remember that you need to create an object `{"payload":"z"}` for each output.

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 10:25 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/14 "2019-08-04T10:25:27Z")

</div>

> [@Steve-Mcl](#):
>
> as you need to assign 1 to msg.payload before returning.

Ok. but as I think I wrote the code - the first one - msg1, msg2, msg3, and msg4 are sent back.  
msg.payload isn't sent back.

So.....

as I have to send a `0` and `1` on all outputs.

It would be something like:

```auto
var p = parseInt(msg.payload);
msg.payload = 1;
msg1.payload = 0;
if (p ===0)
{
  return [msg, msg1,msg1,msg1];
} else
if (p ===1)
{
  return [msg1,msg,msg1,msg1];
} else
if (p===2)
{
  return [msg1,msg1,msg,msg1];
} else
if (p===3)
{
  return [msg1,msg1,msg1,msg];
}

```

---

<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:** [4 August 2019 10:27 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/15 "2019-08-04T10:27:47Z")

</div>

It's an assumption on my behalf that the OP doesn't want the outputs to fire if the condition is not met.

If he does, it could be simplified to 1 line...

```auto
return [{payload : msg.payload == 0 ? 1 : 0}, {payload : msg.payload == 1 ? 1 : 0}, {payload : msg.payload == 2 ? 1 : 0}, {payload : msg.payload == 3 ? 1 : 0}];

```

---

<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:** [4 August 2019 10:29 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/16 "2019-08-04T10:29:11Z")

</div>

What are you trying to accomplish, it sounds like something a switch node could do though

---

<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:** [4 August 2019 10:29 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/17 "2019-08-04T10:29:12Z")

</div>

@Trying_to_learn try this ^

---

<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:** [4 August 2019 10:29 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/18 "2019-08-04T10:29:50Z")

</div>

Exactly what I said. But OP says it's academic 🤷‍♂️

---

<div class="post-metadata">

**Author:** ![Trying\_to\_learn](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/trying_to_learn/32/28400_2.png) [@Trying\_to\_learn](https://discourse.nodered.org/u/Trying_to_learn)\
**Post date:** [4 August 2019 10:32 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/19 "2019-08-04T10:32:48Z")

</div>

Um...

No, there are 4 outputs.  
The state of them can only be `0` or `1`.

This code seems to work:

```auto
var msg1 = {};
var p = parseInt(msg.payload);
msg.payload = 1;
msg1.payload = 0;
if (p ===0)
{
  return [msg, msg1,msg1,msg1];
} else
if (p ===1)
{
  return [msg1,msg,msg1,msg1];
} else
if (p===2)
{
  return [msg1,msg1,msg,msg1];
} else
if (p===3)
{
  return [msg1,msg1,msg1,msg];
}

```

Just now asking about the `else` parts.

If the condition is tested:

```auto
if (p === *x*)
{
   ....

```

Ah!

Ok, got it.

As I can't return values, I have to return msg_x_'s.....

I need to have the separate return lines.  
Depending on which one I want to set as `1`.

---

<div class="post-metadata">

**Author:** ![afelix](https://sea2.discourse-cdn.com/flex026/user_avatar/discourse.nodered.org/afelix/32/9743_2.png) [@afelix](https://discourse.nodered.org/u/afelix)\
**Post date:** [4 August 2019 10:39 UTC](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988/20 "2019-08-04T10:39:24Z")

</div>

> [@Trying\_to\_learn](#):
>
> ```auto
> var msg1 = 0; 
> var msg2 = 0; 
> var msg3 = 0; 
> var msg4 = 0; 
> msg.payload = parseInt(msg.payload); 
> node.warn("message payload is " + msg.payload); 
> if (msg.payload === 0) { 
> // 
> msg1.payload = 1; 
> } else if (msg.payload === 1) { 
> // 
> msg2.payload = 1; 
> } else if (msg.payload === 2) { 
> // 
> msg3.payload = 1; 
> } else if (msg.payload === 3) { 
> // 
> msg4.payload = 1; 
> } 
> node.warn("--------"); 
> node.warn(msg1.payload); 
> node.warn(msg2.payload); 
> node.warn(msg3.payload); 
> node.warn(msg4.payload); 
> return [msg1, msg2, msg3, msg4];
> 
> ```

For your code from the first post to work you only need a small change. We can deliver you all kinds of alternative ways to do this, but I feel the understanding on how to get your original code to work might be better.

A couple things to remember: messages returned are `object`s, and the data you access in it are stored in the `payload` property, that’s why you access those through `msg.payload`. In order to put together your own messages to return, you need to make objects with a payload property on them, which you can edit in your if statement.

You create an object by stating  
`var test_message = {};`  
You add properties to an object by stating  
`test_message.payload = 0;`  
However, if that property is added within an if statement, it won’t exist in the else clause, thus if you try to log it later on it is still undefined.  
To add properties to an object at creation time, so they are initialised when logging or returning, the following works:  
`var test_message = { payload: 0}`, or when you prefer it on multiple lines for readability:

```auto
var test_message = {
    payload: 0
}

```

So, to fix the code in your initial post, replace the first four lines that create your four messages by object initialisations with a payload property present:

```auto
var msg1 = { payload: 0}; 
var msg2 = { payload: 0}; 
var msg3 = { payload: 0}; 
var msg4 = { payload: 0}; 

```

Edit: sorry my phone wrangled the original code while quoting I’ll try fo fix the line endings

[Next page](https://discourse.nodered.org/t/multiple-outputs-of-function-node-not-working/13988.md?page=2)