Really struggling with OH 3 ECMAscript rules. Cannot find event and cannot get triggering item

[JustinG]

Hi Greg,
First thing: it will be much easier to get help on your code if you use code fences. See this post here for a quick intro:

How to use code fences

We all have to type this content over and over and over. Here is a posting we can all point to when the topic comes up. Why use code fences? Because rules, sitemap, logs, and configs are all but unreadable when code fences are not used. When to use code fences? Whenever one is posting any sort of code, config, log, and any text where line wrapping, indentation, and using an equal spaced font makes the text more legible. How to use code fences? Use 3 backticks (```)... Or use <code>... …

I’ll do what I can to answer some of the questions you’ve got.

@ubeaut

First question is do I really need to use ECMAscript?

Nope. If the DSL rules have been working for you, you can keep them; DSL is even still an option if/when you upgrade to OH3. Many users find DSL too limiting and prefer one of the other options, you can accomplish most tasks with DSL.

@ubeaut

ir.getItem(event.itemName)

The item registry gives rules access to all the information about every item in OH. The getItem method of the item registry takes a name of an item in string format and returns an item object that gives you access to the item’s properties. You just have to remember that getItem is returning a complex object, not a nicely formatted string with an item name or label. To get that information you then have to call (as you do in one of the examples below) one of the item methods.

@ubeaut

When I type event and then press ctrl-space my only option is events. There is NO event.

event doesn’t seem to be an automatically included object. If you declare it, then it gets populated by the correct properties. If you just add var event to the top of your rule, you should fix this problem. The editor still won’t be able to complete any of the properties of the object, but it should still at least recognize event as a viable variable.

@ubeaut

//The statement below doesn’t work
var device = event.itemName();

Two things here:

1. Most of your references to event were not working, I suspect, because you hadn’t declared event
2. The values that are populated into the event object are properties (values), not methods (functions), so you don’t need the () and instead it should just be event.itemName

@ubeaut

//I want to get the item that triggered the event and put it in below where it says CoffeeMachine_CoffeeMachine
//as the statement below works!
//var device = itemRegistry.getItem(‘CoffeeMachine_CoffeeMachine’).getLabel();

This works because it is a correct usage of the getItem method with a item name string literal as the method parameter. As soon as you get the event object working you will be able to get the item name string dynamically with event.itemName. As it is already a string you won’t even need the toString just:

var device = ir.getItem(event.itemName).getLabel();

and your device variable will now be a string containing the human friendly label of the item that triggered the event.

Hope that helps get you a little further along if you decide to keep trying instead of staying with the DSL (which is OK too).