Hi, I need to generate a counter which counts up to 10 and back to 0. The following function does't work so, I appreciate some help. TIA var dir = 0; var count = context.get("counter") || 0; if(dir === 0){ count = (count+1); context.set("counter", count); if(count === 11){ dir =…

I didn't like that one much, it was clever but not pretty, this is much nicer. var count = ((context.get("counter") || 0) + 1) % 20 msg.payload = count <= 10 ? count : 20 - count context.set("counter", count); return msg; That counts up to 10 which is what was originally asked for, if you actual…

Your dir variable is local to the function and will always be 0. You should get/set it from context in the same way you are storing the counter variable.

You mean this way? I'm still doing it wrong! var dir = context.get("dir") || 0; var count = context.get("counter") || 0; if(dir === 0){ count = (count+1); context.set("counter", count); if(count === 11){ context.set("dir", dir); dir = 1; } msg.payload = count; retur…

You are saving dir back to context before you change its value.

If you remove the two lines msg.payload = count; return msg; from inside each if statement and put them right at the end that will be a bit more efficient. Also if before the return you add context.set("dir", dir); context.set("counter", count); then you can remove all of those from …

[image] Colin: Finally the second if would be better as an else. If you make the changes as Colin suggests, the second if must be changed to an else if.

[image] knolleary: he second if must be changed to an else if Actually else I think. But you are right, as initially posted my 'improvement' is anything but.

Thank you!! I modified the code as suggested and works as well but with fewer lines. var dir = context.get("dir") || 1; var count = context.get("counter") || 0; count = (count+dir); if(count === 11){ dir = -1; } else if(count === 0){ dir = 1; } msg.payload = count; context.set("dir", dir); co…

Or maybe even var dir = context.get("dir") || 1; var count = context.get("counter") || 0; count = (count+dir); if((count-5.5)*dir >= 5.5){ dir = -dir; } msg.payload = count; context.set("dir", dir); context.set("counter", count); return msg; But maybe that is getting a bit too obtuse.

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Colin 7 March 2020 16:12 8

And if you want to write some code that you look and think how nice it is then instead of using 0 and 1 for dir use -1 and 1. Then you can add it to count rather than testing to see what you need to do. When the value gets to the min or max you can negate dir.

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