[behavior] Activating a function from the previous function node

[Nxito]

I was testing something, and i see this behavior with node functions and the node-red.

I have created two function nodes:
-the first one creates a function with node.send ()
-the second calls this function
-I get an error, but the function is performed in the previous node

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I am doing something wrong?
why does this behave like this?

This is not a big problem, it is just that I do not understand the behavior

[Steve-Mcl]

What happens is it works - then the 1st functions .foo() method node.sends a message containing only {"test":"test"} to the 2nd function (which does not contain .functions) - hence the error. If you test for the presence of msg.functions in your 2nd function it wont happen.

Add node.warn(["msg in function 1", msg]) and node.warn(["msg in function 2", msg]) to your functions this should be clearer

[Nxito]

ok, I understood why this gave me an error.
The behavior that I thought this would have is that when activating the function in the second node, it would act on the second, not the first.
or so I think
it may help me for some recursive tasks ,since I could loop with this

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thanks for answering

[Steve-Mcl]

@Nxito

The behavior that I thought this would have is that when activating the function in the second node, it would act on the second, not the first.

No, a function operates where you design it unless you pass in some context to operate on.

There are a few ways (binding / apply etc) but here are 2 of the simpler ways...

First one - you pass in the node context to operate on...

// function 1
msg.functions={
    foo:function(n){
        n.send({"desc":"foo"})
    },
    bar:function(n){ 
        n.send({"desc":"bar"})
    }
}

// function 2
msg.functions.foo(node)
msg.functions.bar(node)

Another way is a function factory...

// function 1
msg.functionFactory=function(_node){
    var node = _node;
    return {
        foo:function(){ node.send({"desc":"foo"}) },
        bar:function(){ node.send({"desc":"bar"}) }
    }
}

// function 2
var ff = new msg.functionFactory(node);
ff.foo()
ff.bar()

demo flow...

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[dceejay]

This will be fine most of the time - at some point in the future if you start to use messaging plugins this may not work as functions are not generally serialisable.

[Steve-Mcl]

@Nxito - what Dave said (I neglected to include the caveat).

The better way (for now) would probably be to include your functions via settings.js

[dceejay]

well - it's only a small caveat and unlikely for most users - but do remember it if it stops working in the future for some "random" reason.

[Nxito]

Thank you very much for the warning, I will keep it in mind