openhab 2.1.1

layout: documentation title: openHAB Javascript Library source: description: "Fairly high-level ES6 library to support automation in openHAB. It provides convenient access to common openHAB functionality within rules including items, things, actions, logging and more."

openHAB Javascript Library

Status npm version

This library aims to be a fairly high-level ES6 library to support automation in openHAB. It provides convenient access to common openHAB functionality within rules including items, things, actions, logging and more.

This library is included by default in the openHAB JavaScript binding.


Default Installation

Install the openHAB JavaScript binding, a version of this library will be automatically installed and available to ECMAScript 2021+ rules created using File Based Rules or UI Based Rules.

By default, openHAB ships with an older JavaScript runtime based on the Nashorn JavaScript engine which is part of the standard JDK. This is referred to as ECMA - 262 Edition 5.1 or application/javascript in the Main UI.

This library is not compatible with this older runtime.

Custom Installation

On openHABian:

  • Open the openHABian config tool: sudo openhabian-config.
  • Select 40 | openHAB Related.
  • Select 46 | Install openhab-js.


  • Go to the JavaScript user scripts directory: cd $OPENHAB_CONF/automation/js.
  • You may need to install npm.
  • Install the latest release: Run npm i openhab.
  • Install the latest development version: Run npm i git+

NPM will create a node_modules directory containing the latest version of this library. This will be used instead of the binding provided version.


UI Based Rules

The quickest way to add rules is through the openHAB Web UI.

Advanced users, or users migrating scripts from existing systems may want to use File Based Rules for managing rules using files in the user configuration directory.

Adding Triggers

Using the openHAB UI, first create a new rule and set a trigger condition.

openHAB Rule Configuration

Adding Actions

Select "Add Action" and then select "Run Script" with "ECMAScript 262 Edition 11". It’s important this is "Edition 11" or higher, earlier versions will not work. This will bring up an empty script editor where you can enter your JavaScript.

openHAB Rule Engines

You can now write rules using standard ES6 JavaScript along with the included openHAB standard library.

openHAB Rule Script

For example, turning a light on:

console.log("Kitchen Light State", items.getItem("KitchenLight").state);

Sending a notification

actions.NotificationAction.sendNotification("", "Balcony door is open");

Querying the status of a thing

const thingStatusInfo = actions.Things.getThingStatusInfo("zwave:serial_zstick:512");
console.log("Thing status",thingStatusInfo.getStatus());

See openhab-js for a complete list of functionality.

UI Event Object

NOTE: Note that event object is different in UI based rules and file based rules! This section is only valid for UI based rules. If you use file based rules, refer to file based rules event object documentation.

When you use "Item event" as trigger (i.e. "[item] received a command", "[item] was updated", "[item] changed"), there is additional context available for the action in a variable called event.

This tables gives an overview over the event object for most common trigger types:

Property Name Type Trigger Types Description Rules DSL Equivalent
itemState sub-class of org.openhab.core.types.State [item] changed, [item] was updated State that triggered event triggeringItem.state
oldItemState sub-class of org.openhab.core.types.State [item] changed Previous state of Item or Group that triggered event previousState
itemCommand sub-class of org.openhab.core.types.Command [item] received a command Command that triggered event receivedCommand
itemName string all Name of Item that triggered event
type string all Type of event that triggered event ("ItemStateEvent", "ItemStateChangedEvent", "ItemCommandEvent", ...) N/A

Note that in UI based rules event.itemState, event.oldItemState, and event.itemCommand are Java types (not JavaScript), and care must be taken when comparing these with JavaScript types:

var { ON } = require("@runtime")

console.log(event.itemState == "ON")  // WRONG. Java type does not equal with string, not even with "relaxed" equals (==) comparison
console.log(event.itemState.toString() == "ON")  // OK. Comparing strings
console.log(event.itemState == ON)  // OK. Comparing Java types

NOTE: Even with String items, simple comparison with == is not working as one would expect! See below example:

// Example assumes String item trigger
console.log(event.itemState == "test") // WRONG. Will always log "false"
console.log(event.itemState.toString() == "test") // OK

Scripting Basics

The openHAB JSScripting runtime attempts to provide a familiar environment to Javascript developers.


Scripts may include standard NPM based libraries by using CommonJS require. The library search will look in the path automation/js/node_modules in the user configuration directory.


The JS Scripting binding supports the standard console object for logging. Script debug logging is enabled by default at the INFO level, but can be configured using the console logging commands.

log:set DEBUG org.openhab.automation.script

The default logger name prefix is org.openhab.automation.script, this can be changed by assigning a new string to the loggerName property of the console.

Please be aware that messages might not appear in the logs if the logger name does not start with org.openhab. This behaviour is due to log4j2 requiring definition for each logger prefix.

console.loggerName = "org.openhab.custom"

Supported logging functions include:

  • console.log(obj1 [, obj2, ..., objN])
  • [, obj2, ..., objN])
  • console.warn(obj1 [, obj2, ..., objN])
  • console.error(obj1 [, obj2, ..., objN])
  • console.debug(obj1 [, obj2, ..., objN])
  • console.trace(obj1 [, obj2, ..., objN])

Where obj1 ... objN is a list of JavaScript objects to output. The string representations of each of these objects are appended together in the order listed and output.

See for more information about console logging.


JS Scripting provides access to the global setTimeout, setInterval, clearTimeout and clearInterval methods specified in the Web APIs.

When a script is unloaded, all created timeouts and intervals are automatically cancelled.


The global setTimeout() method sets a timer which executes a function once the timer expires. setTimeout() returns a timeoutId (a positive integer value) which identifies the timer created.

var timeoutId = setTimeout(callbackFunction, delay);

delay is an integer value that represents the amount of milliseconds to wait before the timer expires.

The global clearTimeout(timeoutId) method cancels a timeout previously established by calling setTimeout().


The global setInterval() method repeatedly calls a function, with a fixed time delay between each call. setInterval() returns an intervalId (a positive integer value) which identifies the interval created.

var intervalId = setInterval(callbackFunction, delay);

delay is an integer value that represents the amount of milliseconds to wait before the timer expires.

The global clearInterval(intervalId) method cancels a timed, repeating action which was previously established by a call to setInterval().

Accessing Variables

You can access all variables of the current context in the created timers.

Note: Variables can be mutated (changed) after the timer has been created. Be aware that this can lead to unattended side effects, e.g. when you change the variable after timer creation, which can make debugging quite difficult!

var myVar = 'Hello world!';

// Schedule a timer that expires in ten seconds
setTimeout(() => {`Timer expired with myVar = "${myVar}"`);
}, 10000);

myVar = 'Hello mutation!'; // When the timer runs, it will log "Hello mutation!" instead of "Hello world!"

If you need to pass some variables to the timer but avoid that they can get mutated, use a function generator.

Pass variables using a function generator

This allows you to pass variables to the timer's callback function during timer creation. The variables can NOT be mutated after the timer function generator was used to create the callback function.

// Function generator for the timer's callback function
function cbFuncGen (myVariable) {
  return function () {`Timer expired with myVar = "${myVariable}"`);

var myVar = 'Hello world!';

// Schedule a timer that expires in ten seconds
setTimeout(cbFuncGen(myVar), 10000);

myVar = 'Hello mutation!'; // When the timer runs, it will log "Hello world!"


For file based rules, scripts will be loaded from automation/js in the user configuration directory.

NPM libraries will be loaded from automation/js/node_modules in the user configuration directory.

Deinitialization Hook

It is possible to hook into unloading of a script and register a function that is called when the script is unloaded.

require('@runtime').lifecycleTracker.addDisposeHook(() => functionToCall());

// Example
require('@runtime').lifecycleTracker.addDisposeHook(() => {
  console.log("Deinitialization hook runs...")

Standard Library

Full documentation for the openHAB JavaScript library can be found at openhab-js.


The items namespace allows interactions with openHAB items.

See openhab-js : items for full API documentation.

  • items : object
    • .getItem(name, nullIfMissing) ⇒ Item
    • .getItems() ⇒ Array[Item]
    • .getItemsByTag(...tagNames) ⇒ Array[Item]
    • .addItem(itemConfig)
    • .removeItem(itemOrItemName) ⇒ boolean
    • .replaceItem(itemConfig)
    • .safeItemName(s) ⇒ string
const item = items.getItem("KitchenLight");
console.log("Kitchen Light State", item.state);

getItem(name, nullIfMissing)

Calling getItem(...) returns an Item object with the following properties:

  • Item : object
    • .rawItem ⇒ HostItem
    • .history ⇒ ItemHistory
    • .semantics ⇒ ItemSemantics
    • .type ⇒ string
    • .name ⇒ string
    • .label ⇒ string
    • .state ⇒ string
    • .rawState ⇒ HostState
    • .members ⇒ Array[Item]
    • .descendents ⇒ Array[Item]
    • .isUninitialized ⇒ boolean
    • .groupNames ⇒ Array[string]
    • .tags ⇒ Array[string]
    • .getMetadataValue(namespace) ⇒ string
    • .updateMetadataValue(namespace, value) ⇒ string
    • .upsertMetadataValue(namespace, value) ⇒ boolean
    • .updateMetadataValues(namespaceToValues)
    • .sendCommand(value)
    • .sendCommandIfDifferent(value) ⇒ boolean
    • .postUpdate(value)
    • .addGroups(...groupNamesOrItems)
    • .removeGroups(...groupNamesOrItems)
    • .addTags(...tagNames)
    • .removeTags(...tagNames)
const item = items.getItem("KitchenLight");
//send a ON command
//Post an update
//Get state
console.log("KitchenLight state", item.state)


Calling addItem(itemConfig) or replaceItem(itemConfig) requires the itemConfig object with the following properties:

  • itemConfig : object
    • .type ⇒ string
    • .name ⇒ string
    • .label ⇒ string
    • .category (icon) ⇒ string
    • .groups ⇒ Array[string]
    • .tags ⇒ Array[string]
    • .channels ⇒ string | Object { channeluid: { config } }
    • .metadata ⇒ Object { namespace: value } | Object { namespace: { value: value , config: { config } } }
    • .giBaseType ⇒ string
    • .groupFunction ⇒ string

Note: .type and .name are required. Basic UI and the mobile apps need metadata.stateDescription.config.pattern to render the state of an Item.


// more advanced example
  type: 'String',
  name: 'Hallway_Light',
  label: 'Hallway Light',
  category: 'light',
  groups: ['Hallway', 'Light'],
  tags: ['Lightbulb'],
  channels: {
    'binding:thing:device:hallway#light': {},
    'binding:thing:device:livingroom#light': { 
      profile: 'system:follow' 
  metadata: {
    expire: '10m,command=1',
    stateDescription: {
      config: {
        pattern: '%d%%',
        options: '1=Red, 2=Green, 3=Blue'
// minimal example
  type: 'Switch',
  name: 'MySwitch',
  metadata: {
    stateDescription: {
      config: {
        pattern: '%s'

See openhab-js : ItemConfig for full API documentation.


Calling Item.history returns a ItemHistory object with the following functions:

  • ItemHistory :object
    • .averageBetween(begin, end, serviceId) ⇒ number | null
    • .averageSince(timestamp, serviceId) ⇒ number | null
    • .changedBetween(begin, end, serviceId) ⇒ boolean
    • .changedSince(timestamp, serviceId) ⇒ boolean
    • .deltaBetween(begin, end, serviceId) ⇒ number | null
    • .deltaSince(timestamp, serviceId) ⇒ number | null
    • .deviationBetween(begin, end, serviceId) ⇒ number | null
    • .deviationSince(timestamp, serviceId) ⇒ number | null
    • .evolutionRateBetween(begin, end, serviceId) ⇒ number | null
    • .evolutionRateSince(timestamp, serviceId) ⇒ number | null
    • .historicState(timestamp, serviceId) ⇒ string | null
    • .lastUpdate(serviceId) ⇒ ZonedDateTime | null
    • .latestState(serviceId) ⇒ string | null
    • .maximumBetween(begin, end, serviceId) ⇒ string | null
    • .maximumSince(timestamp,serviceId) ⇒ string | null
    • .minimumSince(begin, end, serviceId) ⇒ string | null
    • .minimumSince(timestamp, serviceId) ⇒ string | null
    • .persist(serviceId)
    • .previousState(skipEqual, serviceId) ⇒ string | null
    • .sumBetween(begin, end, serviceId) ⇒ number | null
    • .sumSince(timestamp, serviceId) ⇒ number | null
    • .updatedBetween(begin, end, serviceId) ⇒ boolean
    • .updatedSince(timestamp, serviceId) ⇒ boolean
    • .varianceBetween(begin, end, serviceId) ⇒ number | null
    • .varianceSince(timestamp, serviceId) ⇒ number | null

Note: serviceId is optional, if omitted, the default persistence service will be used.

var yesterday = new Date(new Date().getTime() - (24 * 60 * 60 * 1000));
var item = items.getItem('KitchenDimmer');
console.log('KitchenDimmer averageSince', item.history.averageSince(yesterday));

See openhab-js : ItemHistory for full API documentation.


The Things namespace allows to interact with openHAB Things.

See openhab-js : things for full API documentation.

  • things : object
    • .getThing(uid, nullIfMissing) ⇒ Thing
    • .getThings() ⇒ Array.<Thing>

getThing(uid, nullIfMissing)

Calling getThing(...) returns a Thing object with the following properties:

  • Thing : object
    • .bridgeUID ⇒ String
    • .label ⇒ String
    • .location ⇒ String
    • .status ⇒ String
    • .statusInfo ⇒ String
    • .thingTypeUID ⇒ String
    • .uid ⇒ String
    • .isEnabled ⇒ Boolean
    • .setLabel(label)
    • .setLocation(location)
    • .setProperty(name, value)
    • .setEnabled(enabled)
const thing = things.getThing('astro:moon:home');
console.log('Thing label: ' + thing.label);
// Set Thing location
thing.setLocation('living room');
// Disable Thing


The actions namespace allows interactions with openHAB actions. The following are a list of standard actions.

See openhab-js : actions for full API documentation and additional actions.

Audio Actions

See openhab-js : actions.Audio for complete documentation.


See openhab-js : actions.BusEvent for complete documentation.

Ephemeris Actions

See openhab-js : actions.Ephemeris for complete documentation.

Ephemeris is a way to determine what type of day today or a number of days before or after today is. For example, a way to determine if today is a weekend, a bank holiday, someone’s birthday, trash day, etc.

Additional information can be found on the Ephemeris Actions Docs as well as the Ephemeris JavaDoc.

// Example
let weekend = actions.Ephemeris.isWeekend();

Exec Actions

See openhab-js : actions.Exec for complete documentation.

Execute a command line.

// Execute command line.
actions.Exec.executeCommandLine('echo', 'Hello World!');

// Execute command line with timeout.
let Duration = Java.type('java.time.Duration');
actions.Exec.executeCommandLine(Duration.ofSeconds(20), 'echo', 'Hello World!');

// Get response from command line.
let response = actions.Exec.executeCommandLine('echo', 'Hello World!');

// Get response from command line with timeout.
response = actions.Exec.executeCommandLine(Duration.ofSeconds(20), 'echo', 'Hello World!');

HTTP Actions

See openhab-js : actions.HTTP for complete documentation.

// Example GET Request
var response = actions.HTTP.sendHttpGetRequest('<url>');

Replace <url> with the request url.

ScriptExecution Actions

The ScriptExecution actions provide the callScript(string scriptName) method, which calls a script located at the $OH_CONF/scripts folder, as well as the createTimer method.

You can also create timers using the native JS methods for timer creation, your choice depends on the versatility you need. Sometimes, using setTimer is much faster and easier, but other times, you need the versatility that createTimer provides.

Keep in mind that you should somehow manage the timers you create using createTimer, otherwise you could end up with unmanagable timers running until you restart openHAB. A possible solution is to store all timers in an array and cancel all timers in the Deinitialization Hook.

actions.ScriptExecution.createTimer(time.ZonedDateTime instant, function callback);

actions.ScriptExecution.createTimer(string identifier, time.ZonedDateTime instant, function callback);

createTimer accepts the following arguments:

  • string identifier (optional): Identifies the timer by a string, used e.g. for logging errors that occur during the callback execution.
  • time.ZonedDateTime instant: Point in time when the callback should be executed.
  • function callback: Callback function to execute when the timer expires.

createTimer returns an openHAB Timer, that provides the following methods:

  • cancel(): Cancels the timer. ⇒ boolean: true, if cancellation was successful
  • getExecutionTime(): The scheduled execution time or null if timer was cancelled. ⇒ time.ZonedDateTime or null
  • isActive(): Whether the scheduled execution is yet to happen. ⇒ boolean
  • isCancelled(): Whether the timer has been cancelled. ⇒ boolean
  • hasTerminated(): Whether the scheduled execution has already terminated. ⇒ boolean
  • reschedule(time.ZonedDateTime): Reschedules a timer to a new starting time. This can also be called after a timer has terminated, which will result in another execution of the same code. ⇒ boolean: true, if rescheduling was successful
var now =;

// Function to run when the timer goes off.
function timerOver () {'The timer expired.');

// Create the Timer.
var myTimer = actions.ScriptExecution.createTimer('My Timer', now.plusSeconds(10), timerOver);

// Cancel the timer.

// Check whether the timer is active. Returns true if the timer is active and will be executed as scheduled.
var active = myTimer.isActive();

// Reschedule the timer.

See openhab-js : actions.ScriptExecution for complete documentation.

Semantics Actions

See openhab-js : actions.Semantics for complete documentation.

Thing Actions

It is possible to get the actions for a Thing using actions.Things.getActions(bindingId, thingUid), e.g. actions.Things.getActions('network', 'network:pingdevice:pc').

See openhab-js : actions.Things for complete documentation.

Voice Actions

See openhab-js : actions.Voice for complete documentation.

Cloud Notification Actions

Note: Optional action if openHAB Cloud Connector is installed.

Notification actions may be placed in rules to send alerts to mobile devices registered with an openHAB Cloud instance such as

For available actions have a look at the Cloud Notification Actions Docs.

// Example
actions.NotificationAction.sendNotification('<email>', '<message>'); // to a single myopenHAB user identified by e-mail
actions.NotificationAction.sendBroadcastNotification('<message>'); // to all myopenHAB users

Replace <email> with the e-mail address of the user. Replace <message> with the notification text.


The cache namespace provides a default cache that can be used to set and retrieve objects that will be persisted between reloads of scripts.

See openhab-js : cache for full API documentation.

  • cache : object
    • .get(key, defaultSupplier) ⇒ Object | null
    • .put(key, value) ⇒ Previous Object | null
    • .remove(key) ⇒ Previous Object | null
    • .exists(key) ⇒ boolean

The defaultSupplier provided function will return a default value if a specified key is not already associated with a value.

Example (Get a previously set value with a default value (times = 0))

let counter = cache.get("counter", () => ({ "times": 0 }));

Example (Get a previously set object)

let counter = cache.get("counter");
if(counter == null){
     counter = {times: 0};
     cache.put("counter", counter);


By default, the JS Scripting binding supports console logging like console.log() and console.debug() to the openHAB default log. Additionally, scripts may create their own native openHAB logger using the log namespace.

let logger = log('my_logger');

//prints "Hello World!"
logger.debug("Hello {}!", "world");


openHAB internally makes extensive use of the java.time package. openHAB-JS exports the excellent JS-Joda library via the time namespace, which is a native JavaScript port of the same API standard used in Java for java.time. Anywhere that a native Java ZonedDateTime or Duration is required, the runtime will automatically convert a JS-Joda ZonedDateTime or Duration to its Java counterpart.

The exported JS-Joda library is also extended with convenient functions relevant to openHAB usage.


var now =;
var yesterday =;
var item = items.getItem("Kitchen");
console.log("averageSince", item.history.averageSince(yesterday));
actions.Exec.executeCommandLine(time.Duration.ofSeconds(20), 'echo', 'Hello World!');

See JS-Joda for more examples and complete API usage.


There will be times when this automatic conversion is not available (for example when working with date times within a rule). To ease having to deal with these cases a time.toZDT() function will accept almost any type that can be converted to a time.ZonedDateTime. The following rules are used during the conversion:

Argument Type Rule Examples
null or undefined time.toZDT();
time.ZonedDateTime passed through unmodified
java.time.ZonedDateTime converted to the time.ZonedDateTime equivalent
JavaScript native Date converted to the equivalent time.ZonedDateTime using SYSTEM as the timezone
number, bingint, java.lang.Number, DecimalType rounded to the nearest integer and added to now as milliseconds time.toZDT(1000);
QuantityType if the units are Time, that time is added to now time.toZDT(item.getItem('MyTimeItem').rawState);
items.Item or org.openhab.core.types.Item if the state is supported (see the Type rules in this table, e.g. DecimalType), the state is converted time.toZDT(items.getItem('MyItem'));
String, java.lang.String, StringType parsed based on the following rules
RFC String (output from a Java ZonedDateTime.toString()) parsed time.toZDT(new DateTimeType().getZonedDateTime().toString());
"HH:MM[:ss]" (24 hour time) today's date with the time indicated, seconds is optional time.toZDT('13:45:12');
"kk:mm[:ss][ ]a" (12 hour time) today's date with the time indicated, the space between the time and am/pm and seconds are optional time.toZDT('1:23:45 PM');
Duration String any duration string supported by time.Duration added to now(), see the docs for details time.toZDT('PT1H4M6.789S');

When a type or string that cannot be handled is encountered, an error is thrown.


When you have a time.ZonedDateTime, a new toToday() method was added which will return a new time.ZonedDateTime with today's date but the original's time, accounting for DST changes.

For example, if the time was 13:45 and today was a DST changeover, the time will still be 13:45 instead of one hour off.

const alarm = items.getItem('Alarm');

isBetweenTimes(start, end)

Tests whether this time.ZonedDateTime is between the passed in start and end. However, the function only compares the time portion of the three, ignoring the date portion. The function takes into account times that span midnight. start and end can be anything supported by time.toZDT().


time.toZDT().isBetweenTimes('22:00', '05:00') // currently between 11:00 pm and 5:00 am
time.toZDT().isBetweenTimes(items.getItem('Sunset'), '11:30 PM') // is now between sunset and 11:30 PM?
time.toZDT(items.getItem('StartTime')).isBetweenTimes(time.toZDT(), 'PT1H'); // is the state of StartTime between now and one hour from now

isClose(zdt, maxDur)

Tests to see if the delta between the time.ZonedDateTime and the passed in time.ZonedDateTime is within the passed in time.Duration.

const timestamp = time.toZDT();
// do some stuff
if(timestamp.isClose(time.toZDT(), time.Duration.ofMillis(100))) {
  // did "do some stuff" take longer than 100 msecs to run?


This method on time.ZonedDateTime returns the milliseconds from now to the passed in time.ZonedDateTime.

const timestamp =;


openHAB internally is a Java program. openHAB-JS converts between Java and JavaScript data types and reverse.

See openhab-js : utils for full API documentation.

File Based Rules

The JS Scripting binding will load scripts from automation/js in the user configuration directory. The system will automatically reload scripts when changes are detected to files. Local variable state is not persisted among reloads, see using the cache for a convenient way to persist objects.

File based rules can be created in 2 different ways: using JSRule or the Rule Builder.

See openhab-js : rules for full API documentation.


JSRules provides a simple, declarative syntax for defining rules that will be executed based on a trigger condition

const email = ""

  name: "Balcony Lights ON at 5pm",
  description: "Light will turn on when it's 5:00pm",
  triggers: [triggers.GenericCronTrigger("0 0 17 * * ?")],
  execute: (event) => {
    actions.NotificationAction.sendNotification(email, "Balcony lights are ON");
  tags: ["Balcony", "Lights"],
  id: "BalconyLightsOn"

Note: description, tags and id are optional.

Note: You can use the passed event object to get information about the trigger that triggered the rule. See Event Object for documentation.

Multiple triggers can be added, some example triggers include:

triggers.ChannelEventTrigger('astro:sun:local:rise#event', 'START');

triggers.ItemStateChangeTrigger('my_item', 'OFF', 'ON');

triggers.ItemStateUpdateTrigger('my_item', 'OFF');

triggers.ItemCommandTrigger('my_item', 'OFF');

triggers.GroupStateChangeTrigger('my_group', 'OFF', 'ON');

triggers.GroupStateUpdateTrigger('my_group', 'OFF');

triggers.GroupCommandTrigger('my_group', 'OFF');



triggers.SystemStartlevelTrigger(40)  // Rules loaded

triggers.SystemStartlevelTrigger(50)  // Rule engine started

triggers.SystemStartlevelTrigger(70)  // User interfaces started

triggers.SystemStartlevelTrigger(80)  // Things initialized

triggers.SystemStartlevelTrigger(100) // Startup Complete

triggers.GenericCronTrigger('0 30 16 * * ? *');



You can use null for a trigger parameter to skip its configuration.

See openhab-js : triggers in the API documentation for a full list of all triggers.

Rule Builder

The Rule Builder provides a convenient API to write rules in a high-level, readable style using a builder pattern.

Rules are started by calling rules.when() and can chain together triggers, conditions and operations in the following pattern:

rules.when().triggerType()...if().conditionType().then().operationType(), description, tags, id);

Rule are completed by calling .build(name, description, tags, id) , all parameters are optional and reasonable defaults will be used if omitted.

  • name String rule name - defaults generated name
  • description String Rule description - defaults generated description
  • tags Array of string tag names - defaults empty array
  • id String id - defaults random UUID

A simple example of this would look like:

rules.when().item("F1_Light").changed().then().send("changed").toItem("F2_Light").build("My Rule", "My First Rule");

Operations and conditions can also optionally take functions:

rules.when().item("F1_light").changed().then(event => {
}).build("Test Rule", "My Test Rule");

See Examples for further patterns.

Rule Builder Triggers

  • when()
  • or()
    • .channel(channelName) Specifies a channel event as a source for the rule to fire.
      • .triggered(event) Trigger on a specific event name
    • .cron(cronExpression) Specifies a cron schedule for the rule to fire.
    • .item(itemName) Specifies an item as the source of changes to trigger a rule.
      • .for(duration)
      • .from(state)
      • .to(state)
      • .fromOff()
      • .toOn()
      • .receivedCommand()
      • .receivedUpdate()
    • .memberOf(groupName)
      • .for(duration)
      • .from(state)
      • .to(state)
      • .fromOff()
      • .toOn()
      • .receivedCommand()
      • .receivedUpdate()
    • .system()
      • .ruleEngineStarted()
      • .rulesLoaded()
      • .startupComplete()
      • .thingsInitialized()
      • .userInterfacesStarted()
      • .startLevel(level)
    • .thing(thingName)
      • changed()
      • updated()
      • from(state)
      • to(state)

Additionally, all the above triggers have the following functions:

Rule Builder Conditions

  • if(optionalFunction)
    • .stateOfItem(itemName)
      • is(state)
      • in(state...)

Rule Builder Operations

  • then(optionalFunction)
    • .build(name, description, tags, id)
    • .copyAndSendState()
    • .copyState()
    • .inGroup(groupName)
    • .postIt()
    • .postUpdate(state)
    • .send(command)
    • .sendIt()
    • .sendOff()
    • .sendOn()
    • .sendToggle()

Rule Builder Examples

// Basic rule, when the BedroomLight1 is changed, run a custom function
rules.when().item('BedroomLight1').changed().then(e => {
    console.log("BedroomLight1 state", e.newState)

// Turn on the kitchen light at SUNSET
rules.when().timeOfDay("SUNSET").then().sendOn().toItem("KitchenLight").build("Sunset Rule","turn on the kitchen light at SUNSET");

// Turn off the kitchen light at 9PM and tag rule
rules.when().cron("0 0 21 * * ?").then().sendOff().toItem("KitchenLight").build("9PM Rule", "turn off the kitchen light at 9PM", ["Tag1", "Tag2"]);

// Set the colour of the hall light to pink at 9PM, tag rule and use a custom ID
rules.when().cron("0 0 21 * * ?").then().send("300,100,100").toItem("HallLight").build("Pink Rule", "set the colour of the hall light to pink at 9PM", ["Tag1", "Tag2"], "MyCustomID");

// When the switch S1 status changes to ON, then turn on the HallLight
rules.when().item('S1').changed().toOn().then(sendOn().toItem('HallLight')).build("S1 Rule");

// When the HallLight colour changes pink, if the function fn returns true, then toggle the state of the OutsideLight

// And some rules which can be toggled by the items created in the 'gRules' Group:

// When the HallLight receives a command, send the same command to the KitchenLight
rules.when().item('HallLight').receivedCommand().then().sendIt().toItem('KitchenLight').build("Hall Light", "");

// When the HallLight is updated to ON, make sure that BedroomLight1 is set to the same state as the BedroomLight2

Event Object

NOTE: The event object is different in UI Based Rules and File Based Rules! This section is only valid for File Based Rules. If you use UI Based Rules, refer to UI based rules event object documentation.

When a rule is triggered, the script is provided the event instance that triggered it. The specific data depends on the event type. The event object provides some information about that trigger.

This tables gives an overview over the event object:

Property Name Trigger Types Description Rules DSL Equivalent
oldState ItemStateChangeTrigger, GroupStateChangeTrigger Previous state of Item or Group that triggered event previousState
newState ItemStateChangeTrigger, GroupStateChangeTrigger New state of Item or Group that triggered event N/A
receivedState ItemStateUpdateTrigger, GroupStateUpdateTrigger State of Item that triggered event triggeringItem.state
receivedCommand ItemCommandTrigger, GroupCommandTrigger Command that triggered event receivedCommand
itemName Item****Trigger, Group****Trigger Name of Item that triggered event
receivedEvent ChannelEventTrigger Channel event that triggered event N/A
channelUID ChannelEventTrigger UID of channel that triggered event N/A
oldStatus ThingStatusChangeTrigger Previous state of Thing that triggered event N/A
newStatus ThingStatusChangeTrigger New state of Thing that triggered event N/A
status ThingStatusUpdateTrigger State of Thing that triggered event N/A
thingUID Thing****Trigger UID of Thing that triggered event N/A
eventType all except PWMTrigger, PIDTrigger, time triggers Type of event that triggered event (change, command, triggered, update) N/A
triggerType all except PWMTrigger, PIDTrigger, time triggers Type of trigger that triggered event N/A

All properties are typeof string.

NOTE: Group****Triggers use the equivalent Item****Trigger as trigger for each member. Time triggers do not provide any event instance, therefore no property is populated.

See openhab-js : EventObject for full API documentation.

Advanced Scripting


Third Party Libraries

Loading of third party libraries is supported the same way as loading the openHAB JavaScript library:

var myLibrary = require('my-library');

Note: Only CommonJS require is supported, ES module loading using import is not supported.

Run the npm command from the automation/js folder to install third party libraries, e.g. from npm. This will create a node_modules folder (if it doesn't already exist) and install the library and it's dependencies there.

There are already some openHAB specific libraries available on npm, you may also search the forum for details.

Creating Your Own Library

You can also create your own personal JavaScript library for openHAB, but you can not just create a folder in node_modules and put your library code in it! When it is run, npm will remove everything from node_modules that has not been properly installed.

Follow these steps to create your own library (it's called a CommonJS module):

  1. Create a separate folder for your library outside of automation/js, you may also initialize a Git repository.

  2. Run npm init from your newly created folder; at least provide responses for the name, version and main (e.g. index.js) fields.

  3. Create the main file of your library (index.js) and add some exports:

    const someProperty = 'Hello world!';
    function someFunction () {
      console.log('Hello from your personal library!');
    module.exports = {
  4. Tar it up by running npm pack from your library's folder.

  5. Install it by running npm install <name>-<version>.tgz from the automation/js folder.

  6. After you've installed it with npm, you can continue development of the library inside node_modules.

It is also possible to upload your library to npm to share it with other users.

If you want to get some advanced information, you can read this blog post or just google it.


One can access many useful utilities and types using require("@runtime"), e.g.

var { ON, OFF, QuantityType } = require("@runtime");
// Alternative, more verbose way to achieve the same:
// var runtime = require("@runtime");
// var ON = runtime.ON;
// var OFF = runtime.OFF;
// var QuantityType = runtime.QuantityType;
Variable Description
State org.openhab.core.types.State
Command org.openhab.core.types.Command
Files java.nio.file.Files
Path java.nio.file.Path
Paths java.nio.file.Paths
IncreaseDecreaseType org.openhab.core.library.types.IncreaseDecreaseType
DECREASE IncreaseDecreaseType enum item
INCREASE IncreaseDecreaseType enum item
OnOffType org.openhab.core.library.types.OnOffType
ON OnOffType enum item
OFF OnOffType enum item
OpenClosedType org.openhab.core.library.types.OpenClosedType
OPEN OpenClosedType enum item
CLOSED OpenClosedType enum item
StopMoveType org.openhab.core.library.types.StopMoveType
STOP StopMoveType enum item
MOVE StopMoveType enum item
UpDownType org.openhab.core.library.types.UpDownType
UP UpDownType enum item
DOWN UpDownType enum item
UnDefType org.openhab.core.library.types.UnDefType
NULL UnDefType enum item
UNDEF UnDefType enum item
RefreshType org.openhab.core.library.types.RefreshType
REFRESH RefreshType enum item
NextPreviousType org.openhab.core.library.types.NextPreviusType
NEXT NextPreviousType enum item
PREVIOUS NextPreviousType enum item
PlayPauseType org.openhab.core.library.types.PlayPauseType
PLAY PlayPauseType enum item
PAUSE PlayPauseType enum item
RewindFastforwardType org.openhab.core.library.types.RewindFastforwardType
REWIND RewindFastforwardType enum item
FASTFORWARD RewindFastforwardType enum item
QuantityType org.openhab.core.library.types.QuantityType
StringListType org.openhab.core.library.types.StringListType
RawType org.openhab.core.library.types.RawType
DateTimeType org.openhab.core.library.types.DateTimeType
DecimalType org.openhab.core.library.types.DecimalType
HSBType org.openhab.core.library.types.HSBType
PercentType org.openhab.core.library.types.PercentType
PointType org.openhab.core.library.types.PointType
StringType org.openhab.core.library.types.StringType
SIUnits org.openhab.core.library.unit.SIUnits
ImperialUnits org.openhab.core.library.unit.ImperialUnits
MetricPrefix org.openhab.core.library.unit.MetricPrefix
Units org.openhab.core.library.unit.Units
BinaryPrefix org.openhab.core.library.unit.BinaryPrefix
ChronoUnit java.time.temporal.ChronoUnit
Duration java.time.Duration
ZoneId java.time.ZoneId
ZonedDateTime java.time.ZonedDateTime

require("@runtime") also defines "services" such as items, things, rules, events, actions, ir, itemRegistry. You can use these services for backwards compatibility purposes or ease migration from JSR223 scripts. Generally speaking, you should prefer to use Standard Library provided by this library instead.