What data type is an inject node numeric number?

[Alan UK]

I'm testing a custom node and wanted to try a negative number so I used an inject node to inject -5 as numeric and the receiving custom node crashed.

I added this debug line: node.log("typeof (msg.payload) is "+typeof(msg.payload))

If I inject "-5" as a string the console states: typeof (msg.payload) is string.

If I inject -5 as a numeric it crashes, presumably at the same line.

It would be nice to handle the situation where a user injects a numeric by converting it to a string so the normal logic works.

So what format/data type **to javascript** is a numeric payload?

Thanks for reading.
Alan

[Dave C-J]

it should be type number

the inject node can inject either a number -5 or string "-5"  - up to you...

Your custom node should handle both (or catch the error correctly)

[Alan UK]

Dave, that's what I presumed.

I've now flooded the code with debug messages to the console and have found the error: msg.payload.toLowerCase()

So I've moved the checking code to before:

                  // check for numeric payload
                  if (typeof(msg.payload) === "number") {
                    // convert to string otherwise node crashes
                    msg.payload = msg.payload.toString();
                  }

I suppose I ought to check for other types and reject those ........

Thanks.
Alan

[Colin Law]

On 22 February 2017 at 00:09, Alan UK <al...@cooperfamily.me.uk> wrote:

Dave, that's what I presumed.

I've now flooded the code with debug messages to the console and have found the error: msg.payload.toLowerCase()

So I've moved the checking code to before:

                  // check for numeric payload
                  if (typeof(msg.payload) === "number") {

Note that typeof is an operator, not a function, so the correct syntax is

if (typeof msg.payload) === ...)

I don't know what the effect of putting brackets round a variable before operating on it with the typeof operator so whether that is a factor in your problem I have no idea. Someone with a more in-depth knowledge of js would have to comment on that.

Colin

 

[Dave C-J]

If you really need to make everything into a string... We actually have a function for that. 

    RED.util.ensureString() 

Should do the trick.

[Alan UK]

Thanks Dave & Colin

Dave: that's useful - code now changed.

Colin: Seems both notations are permissible ( typeof xxx or typeof(xxx) ) - see http://www.w3resource.com/javascript/operators/typeof.php. Just happened that when I looked up the syntax I saw the () version first, but why type the () when there is no need to!

[Colin Law]

Oh, you are right. The reference I looked at did not say that. We live and learn.

Thanks

Colin

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