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 Scripting add-on.

• Installation
  • Default Installation
  • Custom Installation
• Compatibility
• Configuration
  • UI Based Rules
  • Adding Triggers
  • Adding Actions
  • UI Event Object
• Scripting Basics
  • let and const
  • require
  • console
  • Timers
  • Paths
  • Deinitialization Hook
• JS Transformation
• Standard Library
  • Items
  • Things
  • Actions
  • Cache
  • Time
  • Quantity
  • Log
  • Utils
• File Based Rules
  • JSRule
  • Rule Builder
  • Event Object
• Advanced Scripting
  • Libraries
  • @runtime

Install the openHAB JavaScript Scripting add-on, a version of this library will be automatically installed and available to ECMAScript 2022+ rules created using File Based Rules or UI Based Rules.

openHAB also provides the JavaScript Scripting (Nashorn) add-on, which is based on the older Nashorn JavaScript engine. This is referred to as ECMA - 262 Edition 5.1 or application/javascript;version=ECMAScript-5.1 in the Main UI. This library is not compatible with this older runtime.

If you want to install the openHAB JavaScript library manually, you need to disable the caching of the internal library in the add-on settings.

On openHABian:

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

Manually:

• 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+https://github.com/openhab/openhab-js.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.

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.

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

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.

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

For example, turning a light on:

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

Sending a notification

actions.NotificationAction.sendNotification("romeo@montague.org", "Balcony door is open");

Querying the status of a thing

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

See openhab-js for a complete list of functionality.

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. Note that event object is only available when the UI based rule was triggered by an event and is not manually run! Trying to access event on manual run does not work (and will lead to an error), use this.event instead (will be undefined in case of manual run).

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

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

The openHAB JavaScript Scripting runtime attempts to provide a familiar environment to JavaScript developers.

Due to the way how openHAB runs UI based scripts, let, const and class are not supported at top-level. Use var instead or wrap your script inside a self-invoking function:

// Wrap script inside a self-invoking function:
(function (data) {
  const C = 'Hello world';
  console.log(C);
})(this.event);

// Defining a class using var:
var Tree = class {
  constructor (height) {
    this.height = height;
  }
}

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. See libraries for more information.

The JS Scripting binding supports the standard console object for logging. Script logging is enabled by default at the INFO level (messages from console.debug and console.trace won't be displayed), but can be configured using the openHAB console:

log:set DEBUG org.openhab.automation.script
log:set TRACE org.openhab.automation.script
log:set DEFAULT org.openhab.automation.script

The default logger name consists of the prefix org.openhab.automation.script and the script’s individual part .file.filename or .ui.ruleUID. This logger name can be changed by assigning a new string to the loggerName property of the console:

console.loggerName = 'org.openhab.custom';

Please be aware that messages do not appear in the logs if the logger name does not start with org.openhab. This behaviour is due to log4j2 requiring a setting for each logger prefix in $OPENHAB_USERDATA/etc/log4j2.xml (on openHABian: /srv/openhab-userdata/etc/log4j2.xml).

Supported logging functions include:

• console.log(obj1 [, obj2, ..., objN])
• console.info(obj1 [, 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 https://developer.mozilla.org/en-US/docs/Web/API/console for more information about console logging.

Note: openhab-js is logging to org.openhab.automation.openhab-js.

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, param1, /* ... */ paramN);

delay is an integer value that represents the amount of milliseconds to wait before the timer expires. param1 ... paramN are optional, additional arguments which are passed through to the callbackFunction.

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

If you need a more verbose way of creating timers, consider to use createTimer instead.

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, param1, /* ... */ paramN);

delay is an integer value that represents the amount of milliseconds to wait before the timer expires. param1 ... paramN are optional, additional arguments which are passed through to the callbackFunction.

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

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(() => {
  console.info(`Timer expired with variable value = "${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, pass those variables as parameters to setTimeout/setInterval or createTimer:

var myVar = 'Hello world!';

// Schedule a timer that expires in ten seconds
setTimeout((myVariable) => {
  console.info(`Timer expired with variable value = "${myVariable}"`);
}, 10000, myVar); // Pass one or more variables as parameters here. They are passed through to the callback function.

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

This also works for timers created with actions.ScriptExecution.createTimer.

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.

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...")
});

openHAB provides several data transformation services as well as the script transformations, that are available from the framework and need no additional installation. It allows transforming values using any of the available scripting languages, which means JavaScript Scripting is supported as well. See the transformation docs for more general information on the usage of script transformations.

Use JavaScript Scripting as script transformation by:

1. Creating a script in the $OPENHAB_CONF/transform folder with the .js extension. The script should take one argument input and return a value that supports toString() or null:

   (function(data) {
     // Do some data transformation here, e.g.
     return "String has" + data.length + "characters";
   })(input);

2. Using JS(<scriptname>.js):%s as Item state transformation.

3. Passing parameters is also possible by using a URL like syntax: JS(<scriptname>.js?arg=value). Parameters are injected into the script and can be referenced like variables.

Simple transformations can aso be given as an inline script: JS(|...), e.g. JS(|"String has " + input.length + "characters"). It should start with the | character, quotes within the script may need to be escaped with a backslash \ when used with another quoted string as in text configurations.

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

The openHAB JavaScript library provides type definitions for most of its APIs to enable code completion is IDEs like VS Code. To use the type definitions, install the openhab npm package (read the installation guide for more information), and import the used namespaces with const { rules, triggers, items } = require('openhab'); (adjust this to your needs). If an API does not provide type definitions and therefore autocompletion won't work, the documentation will include a note.

The items namespace allows interactions with openHAB Items. Anywhere a native openHAB Item is required, the runtime will automatically convert the JS-Item to its Java counterpart.

See openhab-js : items for full API documentation.

• items : object
  • .NAME ⇒ Item
  • .existsItem(name) ⇒ boolean
  • .getItem(name, nullIfMissing) ⇒ Item
  • .getItems() ⇒ Array[Item]
  • .getItemsByTag(...tagNames) ⇒ Array[Item]
  • .addItem(itemConfig)
  • .removeItem(itemOrItemName) ⇒ boolean
  • .replaceItem(itemConfig)
  • .safeItemName(s) ⇒ string

var item = items.KitchenLight;
console.log("Kitchen Light State", item.state);

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

• Item : object
  • .rawItem ⇒ HostItem
  • .persistence ⇒ ItemPersistence
  • .semantics ⇒ ItemSemantics
  • .type ⇒ string
  • .name ⇒ string
  • .label ⇒ string
  • .state ⇒ string
  • .numericState ⇒ number|null: State as number, if state can be represented as number, or null if that's not the case
  • .quantityState ⇒ Quantity|null: Item state as Quantity or null if state is not Quantity-compatible or without unit
  • .rawState ⇒ HostState
  • .members ⇒ Array[Item]
  • .descendents ⇒ Array[Item]
  • .isUninitialized ⇒ boolean
  • .groupNames ⇒ Array[string]
  • .tags ⇒ Array[string]
  • .getMetadata(namespace) ⇒ object|null
  • .replaceMetadata(namespace, value, configuration) ⇒ object
  • .removeMetadata(namespace) ⇒ object|null
  • .sendCommand(value): value can be a string, a time.ZonedDateTime or a Quantity
  • .sendCommandIfDifferent(value) ⇒ boolean: value can be a string, a time.ZonedDateTime or a Quantity
  • .sendIncreaseCommand(value) ⇒ boolean: value can be a number, or a Quantity
  • .sendDecreaseCommand(value) ⇒ boolean: value can be a number, or a Quantity
  • .sendToggleCommand(): Sends a command to flip the Item's state (e.g. if it is 'ON' an 'OFF' command is sent).
  • .postUpdate(value): value can be a string, a time.ZonedDateTime or a Quantity
  • .addGroups(...groupNamesOrItems)
  • .removeGroups(...groupNamesOrItems)
  • .addTags(...tagNames)
  • .removeTags(...tagNames)

// Equivalent to items.KitchenLight
var item = items.getItem("KitchenLight");
// Send an ON command
item.sendCommand("ON");
// Post an update
item.postUpdate("OFF");
// Get state
console.log("KitchenLight state", item.state);

See openhab-js : Item for full API documentation.

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.

Example:

// more advanced example
items.replaceItem({
  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
items.replaceItem({
  type: 'Switch',
  name: 'MySwitch',
  metadata: {
    stateDescription: {
      config: {
        pattern: '%s'
      }
    }
  }
});

See openhab-js : ItemConfig for full API documentation.

Calling Item.persistence returns an ItemPersistence object with the following functions:

• ItemPersistence :object
  • .averageSince(timestamp, serviceId) ⇒ PersistedState | null
  • .averageUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .averageBetween(begin, end, serviceId) ⇒ PersistedState | null
  • .changedSince(timestamp, serviceId) ⇒ boolean
  • .changedUntil(timestamp, serviceId) ⇒ boolean
  • .changedBetween(begin, end, serviceId) ⇒ boolean
  • .countSince(timestamp, serviceId) ⇒ number
  • .countUntil(timestamp, serviceId) ⇒ number
  • .countBetween(begin, end, serviceId) ⇒ number
  • .countStateChangesSince(timestamp, serviceId) ⇒ number
  • .countStateChangesUntil(timestamp, serviceId) ⇒ number
  • .countStateChangesBetween(begin, end, serviceId) ⇒ number
  • .deltaSince(timestamp, serviceId) ⇒ PersistedState | null
  • .deltaUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .deltaBetween(begin, end, serviceId) ⇒ PersistedState | null
  • .deviationSince(timestamp, serviceId) ⇒ PersistedState | null
  • .deviationUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .deviationBetween(begin, end, serviceId) ⇒ PersistedState | null
  • .evolutionRateSince(timestamp, serviceId) ⇒ number | null
  • .evolutionRateUntil(timestamp, serviceId) ⇒ number | null
  • .evolutionRateBetween(begin, end, serviceId) ⇒ number | null
  • .getAllStatesSince(timestamp, serviceId) ⇒ Array[PersistedItem]
  • .getAllStatesUntil(timestamp, serviceId) ⇒ Array[PersistedItem]
  • .getAllStatesBetween(begin, end, serviceId) ⇒ Array[PersistedItem]
  • .lastUpdate(serviceId) ⇒ ZonedDateTime | null
  • .nextUpdate(serviceId) ⇒ ZonedDateTime | null
  • .lastChange(serviceId) ⇒ ZonedDateTime | null
  • .nextChange(serviceId) ⇒ ZonedDateTime | null
  • .maximumSince(timestamp, serviceId) ⇒ PersistedItem | null
  • .maximumUntil(timestamp, serviceId) ⇒ PersistedItem | null
  • .maximumBetween(begin, end, serviceId) ⇒ PersistedItem | null
  • .minimumSince(timestamp, serviceId) ⇒ PersistedItem | null
  • .minimumUntil(timestamp, serviceId) ⇒ PersistedItem | null
  • .minimumBetween(begin, end, serviceId) ⇒ PersistedItem | null
  • .medianSince(timestamp, serviceId) ⇒ PersistedState | null
  • .medianUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .medianBetween(begin, end, serviceId) ⇒ PersistedState | null
  • .persist(serviceId): Tells the persistence service to store the current Item state, which is then done asynchronously. Warning: This has the side effect, that if the Item state changes shortly after .persist has been called, the new Item state will be persisted. See JSDoc for a possible work-around.
  • .persist(timestamp, state, serviceId): Tells the persistence service to store the given state at the given timestamp, which is then done asynchronously.
  • .persist(timeSeries, serviceId): Tells the persistence service to store the given TimeSeries, which is then done asynchronously.
  • .persistedState(timestamp, serviceId) ⇒ PersistedItem | null
  • .previousState(skipEqual, serviceId) ⇒ PersistedItem | null
  • .nextState(skipEqual, serviceId) ⇒ PersistedItem | null
  • .sumSince(timestamp, serviceId) ⇒ PersistedState | null
  • .sumUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .sumBetween(begin, end, serviceId) ⇒ PersistedState | null
  • .updatedSince(timestamp, serviceId) ⇒ boolean
  • .updatedUntil(timestamp, serviceId) ⇒ boolean
  • .updatedBetween(begin, end, serviceId) ⇒ boolean
  • .varianceSince(timestamp, serviceId) ⇒ PersistedState | null
  • .varianceUntil(timestamp, serviceId) ⇒ PersistedState | null
  • .varianceBetween(begin, end, serviceId) ⇒ PersistedState | 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.KitchenDimmer;
console.log('KitchenDimmer averageSince', item.persistence.averageSince(yesterday));

The PersistedState object contains the following properties, representing Item state:

• state: State as string
• numericState: State as number, if state can be represented as number, or null if that's not the case
• quantityState: Item state as Quantity or null if state is not Quantity-compatible
• rawState: State as Java State object

The PersistedItem object extends PersistedState with the following properties, representing Item state and the respective timestamp:

• timestamp: Timestamp as time.ZonedDateTime
• instant: Timestamp as time.Instant

var midnight = time.toZDT('00:00');
var historic = items.KitchenDimmer.persistence.maximumSince(midnight);
console.log('KitchenDimmer maximum was ', historic.state, ' at ', historic.timestamp);

See openhab-js : ItemPersistence for full API documentation.

A TimeSeries is used to transport a set of states together with their timestamp. It is usually used for persisting historic state or forecasts in a persistence service by using ItemPersistence.persist.

When creating a new TimeSeries, a policy must be chosen - it defines how the TimeSeries is persisted in a persistence service:

• ADD adds the content to the persistence, well suited for persisting historic data.
• REPLACE first removes all persisted elements in the timespan given by begin and end of the TimeSeries, well suited for persisting forecasts.

A TimeSeries object has the following properties and methods:

• policy: The persistence policy, either ADD or REPLACE.
• begin: Timestamp of the first element of the TimeSeries.
• end: Timestamp of the last element of the TimeSeries.
• size: Number of elements in the TimeSeries.
• states: States of the TimeSeries together with their timestamp and sorted by their timestamps. Be aware that this returns a reference to the internal state array, so changes to the array will affect the TimeSeries.
• add(timestamp, state): Add a given state to the TimeSeries at the given timestamp.

The following example shows how to create a TimeSeries:

var timeSeries = new items.TimeSeries('ADD'); // Create a new TimeSeries with policy ADD
timeSeries.add(time.toZDT('2024-01-01T14:53'), Quantity('5 m')).add(time.toZDT().minusMinutes(2), Quantity('0 m')).add(time.toZDT().plusMinutes(5), Quantity('5 m'));
console.log(ts); // Let's have a look at the TimeSeries
items.getItem('MyDistanceItem').persistence.persist(timeSeries, 'influxdb'); // Persist the TimeSeries for the Item 'MyDistanceItem' using the InfluxDB persistence service

The Things namespace allows to interact with openHAB Things.

See openhab-js : things for full API documentation.

• things : object
  • .getThing(uid) ⇒ Thing|null
  • .getThings() ⇒ Array[Thing]

Calling getThing(uid) 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)

var thing = things.getThing('astro:moon:home');
console.log('Thing label: ' + thing.label);
// Set Thing location
thing.setLocation('living room');
// Disable Thing
thing.setEnabled(false);

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

Warning: Please be aware, that (unless not explicitly noted) there is no type conversion from Java to JavaScript types for the return values of actions. Read the JavaDoc linked from the JSDoc to learn about the returned Java types.

Please note that most of the actions currently do not provide type definitions and therefore auto-completion does not work.

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

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

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

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

The CoreUtil actions provide access to parts of the utilities included in openHAB core, see org.openhab.core.util. These include several methods to convert between color types like HSB, RGB, sRGB, RGBW and XY.

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 public holiday, someone’s birthday, trash day, etc.

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

var weekend = actions.Ephemeris.isWeekend();

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.
actions.Exec.executeCommandLine(time.Duration.ofSeconds(20), 'echo', 'Hello World!');

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

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

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

Replace <url> with the request url.

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

// Check if a host is reachable
var reachable = actions.Ping.checkVitality(host, port, timeout); // host: string, port: int, timeout: int

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 setTimeout 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 unmanageable timers running until you restart openHAB. A possible solution is to store all timers in the private cache and let openHAB automatically cancel them when the script is unloaded and the cache is cleared. When using createTimer, please read Accessing Variables to avoid having unexpected results when using variables in timers.

actions.ScriptExecution.createTimer(time.ZonedDateTime zdt, function functionRef, any param1, /* ... */ paramN);

actions.ScriptExecution.createTimer(string identifier, time.ZonedDateTime zdt, function functionRef, any param1, /* ... */ paramN);

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 zdt: Point in time when the callback should be executed.
• function functionRef: Callback function to execute when the timer expires.
• * param1, ..., paramN: Additional arguments which are passed through to the function specified by functionRef.

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 = time.ZonedDateTime.now();

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

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

// Cancel the timer.
myTimer.cancel();

// 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.
myTimer.reschedule(now.plusSeconds(5));

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

openHAB provides various data transformation services which can translate between technical and human-readable values. Usually, they are used directly on Items, but it is also possible to access them from scripts.

console.log(actions.Transformation.transform('MAP', 'en.map', 'OPEN')); // open
console.log(actions.Transformation.transform('MAP', 'de.map', 'OPEN')); // offen

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

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

Requires the openHAB Cloud Connector to be installed.

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

There are three different types of notifications:

• Broadcast Notifications: Sent to all registered devices and shown as notification on these devices.
• Standard Notifications: Sent to the registered devices of the specified user and shown as notification on his devices.
• Log Notifications: Only shown in the notification log, e.g. inside the Android and iOS Apps.

In addition to that, notifications can be updated later be re-using the same referenceId and hidden/removed either by referenceId or tag.

To send these three types of notifications, use the notificationBuilder(message) method of the actions namespace. message is optional and may be omitted. It returns a new NotificationBuilder object, which by default sends a broadcast notification and provides the following methods:

• .logOnly(): Send a log notification only.
• .hide(): Hides notification(s) with the specified referenceId or tag (referenceId has precedence over tag).
• .addUserId(emailAddress): By adding the email address(es) of specific openHAB Cloud user(s), the notification is only sent to this (these) user(s). To add multiple users, either call addUserId multiple times or pass mutiple emails as multiple params, e.g. addUserId(emailAddress1, emailAddress2).
• .withIcon(icon): Sets the icon of the notification.
• .withTag(tag): Sets the tag of the notification. Used for grouping notifications and to hide/remove groups of notifications.
• .withTitle(title): Sets the title of the notification.
• .withReferenceId(referenceId): Sets the reference ID of the notification. If none is set, but it might be useful, a random UUID will be generated. The reference ID can be used to update or hide the notification later by using the same reference ID again.
• .withOnClickAction(action): Sets the action to be executed when the notification is clicked.
• .withMediaAttachmentUrl(mediaAttachmentUrl): Sets the URL of a media attachment to be displayed with the notification. This URL must be reachable by the push notification client.
• .addActionButton(label, action): Adds an action button to the notification. Please note that due to Android and iOS limitations, only three action buttons are supported.
• .send() ⇒ string|null: Sends the notification and returns the reference ID or null for log notifications and when hiding notifications.

The syntax for the action parameter is described in openHAB Cloud Connector: Action Syntax.

The syntax for the mediaAttachmentUrl parameter is described in openHAB Cloud Connector.

// Send a simple broadcast notification
actions.notificationBuilder('Hello World!').send();
// Send a broadcast notification with icon, tag and title
actions.notificationBuilder('Hello World!')
  .withIcon('f7:bell_fill').withTag('important').withTitle('Important Notification').send();
// Send a broadcast notification with icon, tag, title, media attachment URL and actions
actions.notificationBuilder('Hello World!')
  .withIcon('f7:bell_fill').withTag('important').withTitle('Important Notification')
  .withOnClickAction('ui:navigate:/page/my_floorplan_page').withMediaAttachmentUrl('http://example.com/image.jpg')
  .addActionButton('Turn Kitchen Light ON', 'command:KitchenLights:ON').addActionButton('Turn Kitchen Light OFF', 'command:KitchenLights:OFF').send();

// Send a simple standard notification to two specific users
actions.notificationBuilder('Hello World!').addUserId('florian@example.com').addUserId('florian@example.org').send();
// Send a standard notification with icon, tag and title to two specific users
actions.notificationBuilder('Hello World!').addUserId('florian@example.com').addUserId('florian@example.org')
  .withIcon('f7:bell_fill').withTag('important').withTitle('Important notification').send();

// Sends a simple log notification
actions.notificationBuilder('Hello World!').logOnly().send();
// Sends a simple log notification with icon and tag
actions.notificationBuilder('Hello World!').logOnly()
  .withIcon('f7:bell_fill').withTag('important').send();

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

The cache namespace provides both a private and a shared cache that can be used to set and retrieve data that will be persisted between subsequent runs of the same or between scripts.

The private cache can only be accessed by the same script and is cleared when the script is unloaded. You can use it to store both primitives and objects, e.g. store timers or counters between subsequent runs of that script. When a script is unloaded and its cache is cleared, all timers (see createTimer) stored in its private cache are automatically cancelled.

The shared cache is shared across all rules and scripts, it can therefore be accessed from any automation language. The access to every key is tracked and the key is removed when all scripts that ever accessed that key are unloaded. If that key stored a timer, the timer will be cancelled. You can use it to store only primitives, as storing objects is not thread-safe and can cause script execution failures.

See openhab-js : cache for full API documentation.

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

var counter = cache.shared.get('counter', () => 0);
console.log('Counter: ' + counter);

Example (Get a previously set value, modify and store it)

var counter = cache.private.get('counter');
counter++;
console.log('Counter: ' + counter);
cache.private.put('counter', counter);

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 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.

Examples:

var now = time.ZonedDateTime.now();
var yesterday = time.ZonedDateTime.now().minusHours(24);
var item = items.Kitchen;
console.log("averageSince", item.persistence.averageSince(yesterday));

actions.Exec.executeCommandLine(time.Duration.ofSeconds(20), 'echo', 'Hello World!');

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

Occasionally, one will need to parse a non-supported date time string or generate one from a ZonedDateTime. To do this you will use JS-Joda DateTimeFormatter and potentially your Locale. However, shipping all the locales with the openhab-js library would lead to an unacceptable large size. Therefore, if you attempt to use the DateTimeFormatter and receive an error saying it cannot find your locale, you will need to manually install your locale and import it into your rule.

JS-Joda Locales includes a list of all the supported locales. Each locale consists of a two letter language indicator followed by a "-" and a two letter dialect indicator: e.g. "EN-US". Installing a locale can be done through the command npm install @js-joda/locale_de-de from the $OPENHAB_CONF/automation/js folder.

To import and use a local into your rule you need to require it and create a DateTimeFormatter that uses it:

var Locale = require('@js-joda/locale_de-de').Locale.GERMAN;
var formatter = time.DateTimeFormatter.ofPattern('dd.MM.yyyy HH:mm').withLocale(Locale);

Converts a java.time.Instant to a JS-Joda Instant.

Converts a java.time.ZonedDateTime to a JS-Joda ZonedDateTime.

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:

If no time zone is explicitly set, the system default time zone is used. 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.

var alarm = items.Alarm;
alarm.postUpdate(time.toZDT(alarm).toToday());

Tests whether this time.ZonedDateTime is before the time passed in timestamp, tested in various ways:

• isBeforeTime only compares the time portion of both, ignoring the date portion
• isBeforeDate only compares the date portion of both, ignoring the time portion
• isBeforeDateTime compares both date and time portions

timestamp can be anything supported by time.toZDT().

Examples:

time.toZDT('22:00').isBeforeTime('23:00')
time.toZDT('2022-12-01T12:00Z').isBeforeDateTime('2022-12-02T13:00Z')

Tests whether this time.ZonedDateTime is after the time passed in timestamp, tested in various ways:

• isAfterTime only compares the time portion of both, ignoring the date portion
• isAfterDate only compares the date portion of both, ignoring the time portion
• isAfterDateTime compares both date and time portions

timestamp can be anything supported by time.toZDT().

// Equivalent to items.Sunset
time.toZDT().isAfterTime(items.getItem('Sunset')) // is now after sunset?
time.toZDT().isAfterDateTime('2022-12-01T12:00Z') // is now after 2022-12-01 noon?

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().

Examples:

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

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

Examples:

time.toZDT().isBetweenDates('2022-06-18', '2023-12-24') // currently between 2022-06-18 and 2023-12-24

Tests whether this time.ZonedDateTime is between the passed in start and end. start and end can be anything supported by time.toZDT().

Examples:

time.toZDT().isBetweenDateTimes('2022-06-18T22:00Z', '2023-12-24T05:00Z') // currently between 2022-06-18 22:00 and 2023-12-24 05:00

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

var 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.

var timestamp = time.ZonedDateTime.now().plusMinutes(5);
console.log(timestamp.getMillisFromNow());

The Quantity class greatly simplifies Quantity handling by providing unit conversion, comparisons and mathematical operations. A Quantity consists of a measurement and its Unit of Measurement (UoM), e.g. 5.7 m (the measurement is 5.7, the unit is m meters).

Internally using the openHAB QuantityType, which relies on javax.measure, it supports all units and dimensions that openHAB supports. If your unit is not listed in the UoM docs, it is very likely that it is still supported, e.g. the Angstrom Å for very small lengths (1 Å = 10 nm). Anywhere a native openHAB QuantityType is required, the runtime will automatically convert the JS-Quantity to its Java counterpart.

Quantity(value) is used without new (it's a factory, not a constructor), pass an amount and a unit to it to create a new Quantity object:

The argument value can be a Quantity-compatible Item, a string, a Quantity instance or an openHAB Java QuantityType.

value strings have the $amount $unit format and must follow these rules:

• $amount is required with a number provided as string
• $unit is optional (unit-less quantities are possible) and can have a prefix like m (milli) or M (mega)
• $unit does not allow whitespaces.
• $unit does allow superscript, e.g. ² instead of ^2.
• $unit requires the * between two units to be present, although you usually omit it (which is mathematically seen allowed, but openHAB needs the *).

Generally, you can expect a unit consisting of two (or more) units to need a *, e.g. Nm is N*m,

Nearly all Units of Measurement (UoM) are expected to work with Quantity. ɡₙ (standard gravity) is known to not work.

// Allowed:
var qty = Quantity('5.75 m');
qty = Quantity('1 N*m');
qty = Quantity('1 m/s');
qty = Quantity('1 m^2/s^2');
qty = Quantity('1 m^2/s^-2'); // negative powers
qty = Quantity('1'); // unitless quantity
qty = Quantity(items.my_uom_item);

// Not allowed:
qty = Quantity('m');
qty = Quantity('1 Nm'); // * is required
qty = Quantity('1 m^2 / s^2'); // whitespaces are not allowed
qty = Quantity('1 m^2 s^2'); // / is required
qty = Quantity('1 m2/s2'); // ^ is required

Note: It is possible to create a unit-less (without unit) Quantity, however there is no advantage over using a number instead.

It is possible to convert a Quantity to a new Quantity with a different unit or to get a Quantity's amount as integer or float:

var qty = Quantity('10.2 °C');

qty = qty.toUnit('°F');
var intValue = qty.int;
var floatValue = qty.float;

toUnit returns a new Quantity with the given unit or null, if conversion to that unit is not possible.

Quantity provides the following methods for comparison:

• equal(value) ⇒ boolean: this Quantity equals to value
• greaterThan(value) ⇒ boolean: this Quantity is greater than value
• greaterThanOrEqual(value) ⇒ boolean: this Quantity is greater than or equal to value
• lessThan(value) ⇒ boolean: this Quantity is less than value
• lessThanOrEqual(value) ⇒ boolean: this Quantity is less than or equal to value

value can be a string or a Quantity, for the string the same rules apply as described above.

• add(value) ⇒ Quantity: value can be a Quantity-compatible Item, a string or a Quantity
• divide(value) ⇒ Quantity: value can be a Quantity-compatible or Number Item, a number, a string or a Quantity
• multiply(value) ⇒ Quantity: value can be a Quantity-compatible or Number Item, a number, a string or a Quantity
• subtract(value) ⇒ Quantity: value can be a Quantity-compatible Item, a string or a Quantity

For the string the same rules apply as described above.

See openhab-js : Quantity for full API documentation.

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.

var logger = log('my_logger');

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

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.

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.

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

var email = "juliet@capulet.org"

rules.JSRule({
  name: "Balcony Lights ON at 5pm",
  description: "Light will turn on when it's 5:00pm",
  triggers: [triggers.GenericCronTrigger("0 0 17 * * ?")],
  execute: (event) => {
    // Equivalent to items.BalconyLights.sendCommand("ON")
    items.getItem("BalconyLights").sendCommand("ON");
    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.ThingStatusUpdateTrigger('some:thing:uuid','OFFLINE');

triggers.ThingStatusChangeTrigger('some:thing:uuid','ONLINE','OFFLINE');

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 * * ? *');

triggers.TimeOfDayTrigger('19:00');

triggers.DateTimeTrigger('MyDateTimeItem');

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

You may use SwitchableJSRule to create a rule that can be enabled and disabled with a Switch Item. As an extension to JSRule, its syntax is the same, however you can specify an Item name (using the switchItemName rule config property) if you don't like the automatically created Item's name.

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

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()...build(name, 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 => {
    console.log(event);
}).build("Test Rule", "My Test Rule");

Note that the Rule Builder currently does not provide type definitions and therefore auto-completion does not work.

See Examples for further patterns.

• 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.
  • .timeOfDay(time): Specifies a time of day in HH:mm for the rule to fire.
  • .item(itemName): Specifies an Item as the source of changes to trigger a rule.
    • .for(duration)
    • .from(state)
    • .fromOn()
    • .fromOff()
    • .to(state)
    • .toOn()
    • .toOff()
    • .receivedCommand()
    • .receivedUpdate()
    • .changed()
  • .memberOf(groupName): Specifies a group Item as the source of changes to trigger the rule.
    • .for(duration)
    • .from(state)
    • .fromOn()
    • .fromOff()
    • .to(state)
    • .toOn()
    • .toOff()
    • .receivedCommand()
    • .receivedUpdate()
    • .changed()
  • .system(): Specifies a system event as a source for the rule to fire.
    • .ruleEngineStarted()
    • .rulesLoaded()
    • .startupComplete()
    • .thingsInitialized()
    • .userInterfacesStarted()
    • .startLevel(level)
  • .thing(thingName): Specifies a Thing event as a source for the rule to fire.
    • changed()
    • updated()
    • from(state)
    • to(state)
  • .dateTime(itemName): Specifies a DateTime Item whose (optional) date and time schedule the rule to fire.
    • .timeOnly(): Only the time of the Item should be compared, the date should be ignored.
    • .withOffset(offset): The offset in seconds to add to the time of the DateTime Item.

Additionally, all the above triggers have the following functions:

• .if() or .if(fn) -> a rule condition
• .then() or .then(fn) -> a rule operation
• .or() -> a rule trigger (chain additional triggers)

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

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

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

// Turn on the kitchen light at SUNSET (using the Astro binding)
rules.when().channel('astro:sun:home:set#event').triggered('START').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().timeOfDay('21:00').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
rules.when().item('HallLight').changed().to('300,100,100').if(fn).then().sendToggle().toItem('OutsideLight').build();

// Turn on the outdoor lights based on a DateTime Item's time portion
rules.when().dateTime('OutdoorLights_OffTime').timeOnly().then().sendOff().toItem('OutdoorLights').build('Outdoor Lights off');

// 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(true).item('HallLight').receivedCommand().then().sendIt().toItem('KitchenLight').build('Hall Light to Kitchen Light');

// When the HallLight is updated to ON, make sure that BedroomLight1 is set to the same state as the BedroomLight2
rules.when(true).item('HallLight').receivedUpdate().then().copyState().fromItem('BedroomLight1').toItem('BedroomLight2').build();

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 table gives an overview over the event object:

All properties are typeof string except for properties contained by raw which are unmodified from the original types.

Please note that when using GenericEventTrigger, the available properties depend on the chosen event types. It is not possible for the openhab-js library to provide type conversions for all properties of all openHAB events, as those are too many. In case the event object does not provide type-conversed properties for your chosen event type, use the payload property to gain access to the event's (Java data type) payload.

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.

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.

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:

   var someProperty = 'Hello world!';
   function someFunction () {
     console.log('Hello from your personal library!');
   }
   
   module.exports = {
     someProperty,
     someFunction
   };

4. Tar it up by running npm pack from your library's folder.

5. Install it by running npm install <path-to-library-folder>/<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.

In most cases, the Standard Library provides pure-JS APIs to interact with the openHAB runtime. Generally speaking, you should therefore prefer to use Standard Library provided by this library instead.

However, in some cases, e.g. when needing a HSBType, one needs to access raw Java utilities and types. This can be achieved by 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;

A list of available utilities and types can be found in the JSR223 Default Preset documentation.

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.