How to calulate length of msg.id

General
1

How to calculate length of msg.id .I want to differentiate between fob id and tag is which are of different sizes .please suggest?

2

Can you post an example of what you mean?

3

Maybe look at JavaScript .length

4

if(length of msg.id==4)
{
do something...
}
if(length of msg.id==8)
{
do something.....
}

5

Yes sir i tried this but no output whats wrong in this please answer

6

Hi @shipra

first we need to understand exactly what type of value you have in msg.id. If you pass it to a Debug node, configured to display msg.id, that will show us what you have got.

If it is a String type of value, then you can use the length function on the String object - https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length

So in this instance, you would get the length of msg.id with msg.id.length().

If msg.id is not a String, but is actually some other type, then it depends on what that type is and what you want from it.

7

Sir i have tried this ,please suggest whats wrong in this
msg.id is a string


var words='${msg.id}';
var i= words.length;
if(i==4)
{
let newMsg1 = {};

newMsg1.topic = `INSERT INTO  NCS_DATABASE3 (Date_and_Time_India,Date_and_Time_UK ,Event_Type ,Event_Description ,Person_ID,Person_Name_Description ,Fob_Tag_ID ,Trade_ID,Door_ID ,Door_Description ,Status)
VALUES ((strftime('%Y-%m-%d %H:%M:%S','now','localtime')),(strftime('%Y-%m-%d %H:%M:%S','now','localtime','-4 hour','-30 minutes')),' ',' ',' ','Shipra Nigam',' ','${msg.id}',' ',' ','DR1 ON')`;
return newMsg1;

}
if(i==8)
{
    let newMsg2 = {};

newMsg2.topic = `INSERT INTO  NCS_DATABASE3 (Date_and_Time_India,Date_and_Time_UK ,Event_Type ,Event_Description ,Person_ID,Person_Name_Description ,Fob_Tag_ID ,Trade_ID,Door_ID ,Door_Description ,Status)
VALUES ((strftime('%Y-%m-%d %H:%M:%S','now','localtime')),(strftime('%Y-%m-%d %H:%M:%S','now','localtime','-4 hour','-30 minutes')),' ',' ',' ','Shipra Nigam','${msg.id}',' ',' ',' ','DR1 ON')`;
return newMsg2;
}
8

Without knowing anything about what you want the code to do, I can only look for JavaScript mistakes.

The first line should be:

var words = msg.id;
9

error coming
check this

SELECT Fob_Tag_ID FROM NCS_DATABASE3 WHERE Fob_Tag_ID='04222436' : msg : Object
object
topic: "SELECT Fob_Tag_ID FROM NCS_DATABASE3 WHERE Fob_Tag_ID='04222436'"
_msgid: "ca43b588.7a0808"
payload: "CR_SUCCESS"
9/10/2020, 6:01:53 PMnode: a4cb6fc0.fed9function : (error)
"TypeError: words.length is not a function"
10

If words.length is not a function (which is what the error tells you), then words is not a String type of object - so therefore msg.id is not a String.

So I go back to my original reply - you need to confirm what type of value msg.id is. Pass it to a Debug node (configured to show msg.id) and then show us what it reports when you pass a message to it.

11

Sir thank you so much now its working.
:slight_smile:

12

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