OutputChannel

The OutputChannel class represents a single output MIDI channel. OutputChannel objects are provided by an Output port which, itself, is made available by a device. The OutputChannel object is derived from the host's MIDI subsystem and should not be instantiated directly.

All 16 OutputChannel objects can be found inside the parent output's channels property.

Since: 3.0.0

Extends: EventEmitter

Constructor

Creates an OutputChannel object.

Parameters

new OutputChannel(output, number)

Parameter	Type	Default	Description
output	Output		The Output this channel belongs to.
number	number		The MIDI channel number (1 - 16).

---

Properties

.eventCount

Type: number
Attributes: read-only

The number of unique events that have registered listeners.

Note: this excludes global events registered with EventEmitter.ANY_EVENT because they are not tied to a specific event.

.eventMap

Type: Object
Attributes: read-only

An object containing a property for each event with at least one registered listener. Each event property contains an array of all the Listener objects registered for the event.

.eventNames

Type: Array.<string>
Attributes: read-only

An array of all the unique event names for which the emitter has at least one registered listener.

Note: this excludes global events registered with EventEmitter.ANY_EVENT because they are not tied to a specific event.

.eventsSuspended

Type: boolean

Whether or not the execution of callbacks is currently suspended for this emitter.

.number

Since: 3.0
Type: number

This channel's MIDI number (1 - 16).

.octaveOffset

Since: 3.0
Type: number

An integer to offset the reported octave of outgoing note-specific messages (noteon, noteoff and keyaftertouch). By default, middle C (MIDI note number 60) is placed on the 4th octave (C4).

Note that this value is combined with the global offset value defined in WebMidi.octaveOffset and with the parent value defined in Output.octaveOffset.

.output

Since: 3.0
Type: Output

The parent Output this channel belongs to.

---

Methods

.addListener(...)

Adds a listener for the specified event. It returns the Listener object that was created and attached to the event.

To attach a global listener that will be triggered for any events, use EventEmitter.ANY_EVENT as the first parameter. Note that a global listener will also be triggered by non-registered events.

Parameters

Signature: addListener(event, callback, [options])

Parameter	Type(s)	Default	Description
event	string Symbol		The event to listen to.
callback	EventEmitter~callback		The callback function to execute when the event occurs.
[options]	Object	{}
[options.context]	Object	this	The value of this in the callback function.
[options.prepend]	boolean	false	Whether the listener should be added at the beginning of the listeners array and thus executed first.
[options.duration]	number	Infinity	The number of milliseconds before the listener automatically expires.
[options.remaining]	number	Infinity	The number of times after which the callback should automatically be removed.
[options.arguments]	array		An array of arguments which will be passed separately to the callback function. This array is stored in the arguments property of the Listener object and can be retrieved or modified as desired.

Return Value

Returns: Listener

The newly created Listener object.

Throws:

• TypeError : The event parameter must be a string or EventEmitter.ANY_EVENT.
• TypeError : The callback parameter must be a function.

.addOneTimeListener(...)

Adds a one-time listener for the specified event. The listener will be executed once and then destroyed. It returns the Listener object that was created and attached to the event.

To attach a global listener that will be triggered for any events, use EventEmitter.ANY_EVENT as the first parameter. Note that a global listener will also be triggered by non-registered events.

Parameters

Signature: addOneTimeListener(event, callback, [options])

Parameter	Type(s)	Default	Description
event	string Symbol		The event to listen to
callback	EventEmitter~callback		The callback function to execute when the event occurs
[options]	Object	{}
[options.context]	Object	this	The context to invoke the callback function in.
[options.prepend]	boolean	false	Whether the listener should be added at the beginning of the listeners array and thus executed first.
[options.duration]	number	Infinity	The number of milliseconds before the listener automatically expires.
[options.arguments]	array		An array of arguments which will be passed separately to the callback function. This array is stored in the arguments property of the Listener object and can be retrieved or modified as desired.

Return Value

Returns: Listener

The newly created Listener object.

Throws:

• TypeError : The event parameter must be a string or EventEmitter.ANY_EVENT.
• TypeError : The callback parameter must be a function.

.emit(...)

Executes the callback function of all the Listener objects registered for a given event. The callback functions are passed the additional arguments passed to emit() (if any) followed by the arguments present in the arguments property of the Listener object (if any).

If the eventsSuspended property is true or the Listener.suspended property is true, the callback functions will not be executed.

This function returns an array containing the return values of each of the callbacks.

It should be noted that the regular listeners are triggered first followed by the global listeners (those added with EventEmitter.ANY_EVENT).

Parameters

Signature: emit(event, ...args)

Parameter	Type(s)	Default	Description
event	string		The event
args	*		Arbitrary number of arguments to pass along to the callback functions

Return Value

Returns: Array

An array containing the return value of each of the executed listener functions.

Throws:

• TypeError : The event parameter must be a string.

.getListenerCount(...)

Returns the number of listeners registered for a specific event.

Please note that global events (those added with EventEmitter.ANY_EVENT) do not count towards the remaining number for a "regular" event. To get the number of global listeners, specifically use EventEmitter.ANY_EVENT as the parameter.

Parameters

Signature: getListenerCount(event)

Parameter	Type(s)	Default	Description
event	string Symbol		The event which is usually a string but can also be the special EventEmitter.ANY_EVENT symbol.

Return Value

Returns: number

An integer representing the number of listeners registered for the specified event.

.getListeners(...)

Returns an array of all the Listener objects that have been registered for a specific event.

Please note that global events (those added with EventEmitter.ANY_EVENT) are not returned for "regular" events. To get the list of global listeners, specifically use EventEmitter.ANY_EVENT as the parameter.

Parameters

Signature: getListeners(event)

Parameter	Type(s)	Default	Description
event	string Symbol		The event to get listeners for.

Return Value

Returns: Array.<Listener>

An array of Listener objects.

.hasListener(...)

Returns true if the specified event has at least one registered listener. If no event is specified, the method returns true if any event has at least one listener registered (this includes global listeners registered to EventEmitter.ANY_EVENT).

Note: to specifically check for global listeners added with EventEmitter.ANY_EVENT, use EventEmitter.ANY_EVENT as the parameter.

Parameters

Signature: hasListener([event], [callback])

Parameter	Type(s)	Default	Description
[event]	string Symbol	(any event)	The event to check
[callback]	function Listener	(any callback)	The actual function that was added to the event or the Listener object returned by addListener().

Return Value

Returns: boolean

.playNote(...)

Plays a note or an array of notes on the channel. The first parameter is the note to play. It can be a single value or an array of the following valid values:

• A Note object
• A MIDI note number (integer between 0 and 127)
• A note name, followed by the octave (e.g. "C3", "G#4", "F-1", "Db7")

The playNote() method sends a note on MIDI message for all specified notes. If a duration is set in the options parameter or in the Note object's duration property, it will also schedule a note off message to end the note after said duration. If no duration is set, the note will simply play until a matching note off message is sent with stopNote() or sendNoteOff().

The execution of the note on command can be delayed by using the time property of the options parameter.

When using Note objects, the durations and velocities defined in the Note objects have precedence over the ones specified via the method's options parameter.

Note: per the MIDI standard, a note on message with an attack velocity of 0 is functionally equivalent to a note off message.

Parameters

Signature: playNote(note, [options])

Parameter	Type(s)	Default	Description
note	number string Note Array.<number> Array.<string> Array.<Note>		The note(s) to play. The notes can be specified by using a MIDI note number (0 - 127), a note identifier (e.g. C3, G#4, F-1, Db7), a Note object or an array of the previous types. When using a note identifier, the octave range must be between -1 and 9. The lowest note is C-1 (MIDI note number 0) and the highest note is G9 (MIDI note number 127).
[options]	object	{}
[options.duration]	number		A positive decimal number larger than 0 representing the number of milliseconds to wait before sending a note off message. If invalid or left undefined, only a note on message will be sent.
[options.attack]	number	0.5	The velocity at which to play the note (between 0 and 1). If the rawAttack option is also defined, it will have priority. An invalid velocity value will silently trigger the default of 0.5.
[options.rawAttack]	number	64	The attack velocity at which to play the note (between 0 and 127). This has priority over the attack property. An invalid velocity value will silently trigger the default of 64.
[options.release]	number	0.5	The velocity at which to release the note (between 0 and 1). If the rawRelease option is also defined, it will have priority. An invalid velocity value will silently trigger the default of 0.5. This is only used with the note off event triggered when options.duration is set.
[options.rawRelease]	number	64	The velocity at which to release the note (between 0 and 127). This has priority over the release property. An invalid velocity value will silently trigger the default of 64. This is only used with the note off event triggered when options.duration is set.
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.removeListener(...)

Removes all the listeners that match the specified criterias. If no parameters are passed, all listeners will be removed. If only the event parameter is passed, all listeners for that event will be removed. You can remove global listeners by using EventEmitter.ANY_EVENT as the first parameter.

To use more granular options, you must at least define the event. Then, you can specify the callback to match or one or more of the additional options.

Parameters

Signature: removeListener([event], [callback], [options])

Parameter	Type(s)	Default	Description
[event]	string		The event name.
[callback]	EventEmitter~callback		Only remove the listeners that match this exact callback function.
[options]	Object
[options.context]	*		Only remove the listeners that have this exact context.
[options.remaining]	number		Only remove the listener if it has exactly that many remaining times to be executed.

.send(...)

Sends a MIDI message on the MIDI output port. If no time is specified, the message will be sent immediately. The message should be an array of 8-bit unsigned integers (0 - 225), a Uint8Array object or a Message object.

It is usually not necessary to use this method directly as you can use one of the simpler helper methods such as playNote(), stopNote(), sendControlChange(), etc.

Details on the format of MIDI messages are available in the summary of MIDI messages from the MIDI Manufacturers Association.

Parameters

Signature: send(message, [options])

Parameter	Type(s)	Default	Description
message	Array.<number> Uint8Array Message		A Message object, an array of 8-bit unsigned integers or a Uint8Array object (not available in Node.js) containing the message bytes.
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The first byte (status) must be an integer between 128 and 255.
• RangeError : Data bytes must be integers between 0 and 255.

.sendAllNotesOff(...)

Sends an all notes off channel mode message. This will make all currently playing notes fade out just as if their key had been released. This is different from the sendAllSoundOff() method which mutes all sounds immediately.

Parameters

Signature: sendAllNotesOff([options])

Parameter	Type(s)	Default	Description
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendAllSoundOff(...)

Sends an all sound off channel mode message. This will silence all sounds playing on that channel but will not prevent new sounds from being triggered.

Parameters

Signature: sendAllSoundOff([options])

Parameter	Type(s)	Default	Description
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendChannelAftertouch(...)

Sends a MIDI channel aftertouch message. For key-specific aftertouch, you should instead use sendKeyAftertouch().

Parameters

Signature: sendChannelAftertouch([pressure], [options])

Parameter	Type(s)	Default	Description
[pressure]	number		The pressure level (between 0 and 1). If the rawValue option is set to true, the pressure can be defined by using an integer between 0 and 127.
[options]	object	{}
[options.rawValue]	boolean	false	A boolean indicating whether the value should be considered a float between 0 and 1.0 (default) or a raw integer between 0 and 127.
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError Invalid channel aftertouch value.

.sendChannelMode(...)

Sends a MIDI channel mode message. The channel mode message to send can be specified numerically or by using one of the following common names:

Type	Number	Shortcut Method
allsoundoff	120	sendAllSoundOff()
resetallcontrollers	121	sendResetAllControllers()
localcontrol	122	sendLocalControl()
allnotesoff	123	sendAllNotesOff()
omnimodeoff	124	sendOmniMode(false)
omnimodeon	125	sendOmniMode(true)
monomodeon	126	sendPolyphonicMode("mono")
polymodeon	127	sendPolyphonicMode("poly")

Note: as you can see above, to make it easier, all channel mode messages also have a matching helper method.

It should be noted that, per the MIDI specification, only localcontrol and monomodeon may require a value that's not zero. For that reason, the value parameter is optional and defaults to 0.

Parameters

Signature: sendChannelMode(command, [value], [options])

Parameter	Type(s)	Default	Description
command	number string		The numerical identifier of the channel mode message (integer between 120 and 127) or its name as a string.
[value]	number	0	The value to send (integer between 0 - 127).
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendControlChange(...)

Since: 3.0.0

Sends a MIDI control change message to the channel at the scheduled time. The control change message to send can be specified numerically (0 to 127) or by using one of the following common names:

Number	Name
0	bankselectcoarse
1	modulationwheelcoarse
2	breathcontrollercoarse
4	footcontrollercoarse
5	portamentotimecoarse
6	dataentrycoarse
7	volumecoarse
8	balancecoarse
10	pancoarse
11	expressioncoarse
12	effectcontrol1coarse
13	effectcontrol2coarse
18	generalpurposeslider3
19	generalpurposeslider4
32	bankselectfine
33	modulationwheelfine
34	breathcontrollerfine
36	footcontrollerfine
37	portamentotimefine
38	dataentryfine
39	volumefine
40	balancefine
42	panfine
43	expressionfine
44	effectcontrol1fine
45	effectcontrol2fine
64	holdpedal
65	portamento
66	sustenutopedal
67	softpedal
68	legatopedal
69	hold2pedal
70	soundvariation
71	resonance
72	soundreleasetime
73	soundattacktime
74	brightness
75	soundcontrol6
76	soundcontrol7
77	soundcontrol8
78	soundcontrol9
79	soundcontrol10
80	generalpurposebutton1
81	generalpurposebutton2
82	generalpurposebutton3
83	generalpurposebutton4
91	reverblevel
92	tremololevel
93	choruslevel
94	celestelevel
95	phaserlevel
96	databuttonincrement
97	databuttondecrement
98	nonregisteredparametercoarse
99	nonregisteredparameterfine
100	registeredparametercoarse
101	registeredparameterfine
120	allsoundoff
121	resetallcontrollers
122	localcontrol
123	allnotesoff
124	omnimodeoff
125	omnimodeon
126	monomodeon
127	polymodeon

As you can see above, not all control change message have a matching name. This does not mean you cannot use the others. It simply means you will need to use their number (0 to 127) instead of their name. While you can still use them, numbers 120 to 127 are usually reserved for channel mode messages. See sendChannelMode() method for more info.

To view a detailed list of all available control change messages, please consult "Table 3 - Control Change Messages" from the MIDI Messages specification.

Note: messages #0-31 (MSB) are paired with messages #32-63 (LSB). For example, message #1 (modulationwheelcoarse) can be accompanied by a second control change message for modulationwheelfine to achieve a greater level of precision. if you want to specify both MSB and LSB for messages between 0 and 31, you can do so by passing a 2-value array as the second parameter.

Parameters

Signature: sendControlChange(controller, value, [options])

Parameter	Type(s)	Default	Description
controller	number string		The MIDI controller name or number (0 - 127).
value	number Array.<number>		The value to send (0-127). You can also use a two-position array for controllers 0 to 31. In this scenario, the first value will be sent as usual and the second value will be sent to the matching LSB controller (which is obtained by adding 32 to the first controller)
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : Controller numbers must be between 0 and 127.
• RangeError : Invalid controller name.
• TypeError : The value array must have a length of 2.

.sendKeyAftertouch(...)

Sends a MIDI key aftertouch message at the scheduled time. This is a key-specific aftertouch. For a channel-wide aftertouch message, use sendChannelAftertouch().

Parameters

Signature: sendKeyAftertouch(target, [pressure], [options])

Parameter	Type(s)	Default	Description
target	number Note string Array.<number> Array.<Note> Array.<string>		The note(s) for which you are sending an aftertouch value. The notes can be specified by using a MIDI note number (0 - 127), a Note object, a note identifier (e.g. C3, G#4, F-1, Db7) or an array of the previous types. When using a note identifier, octave range must be between -1 and 9. The lowest note is C-1 (MIDI note number 0) and the highest note is G9 (MIDI note number 127). When using a note identifier, the octave value will be offset by the local octaveOffset and by Output.octaveOffset and WebMidi.octaveOffset (if those values are not 0). When using a key number, octaveOffset values are ignored.
[pressure]	number	0.5	The pressure level (between 0 and 1). An invalid pressure value will silently trigger the default behaviour. If the rawValue option is set to true, the pressure is defined by using an integer between 0 and 127.
[options]	object	{}
[options.rawValue]	boolean	false	A boolean indicating whether the value should be considered a float between 0 and 1.0 (default) or a raw integer between 0 and 127.
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError Invalid key aftertouch value.

.sendLocalControl(...)

Turns local control on or off. Local control is usually enabled by default. If you disable it, the instrument will no longer trigger its own sounds. It will only send the MIDI messages to its out port.

Parameters

Signature: sendLocalControl([state], [options])

Parameter	Type(s)	Default	Description
[state]	boolean	false	Whether to activate local control (true) or disable it (false).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendMasterTuning(...)

Sends a master tuning message. The value is decimal and must be larger than -65 semitones and smaller than 64 semitones.

Because of the way the MIDI specification works, the decimal portion of the value will be encoded with a resolution of 14bit. The integer portion must be between -64 and 63 inclusively. This function actually generates two MIDI messages: a Master Coarse Tuning and a Master Fine Tuning RPN messages.

Parameters

Signature: sendMasterTuning([value], [options])

Parameter	Type(s)	Default	Description
[value]	number	0.0	The desired decimal adjustment value in semitones (-65 < x < 64)
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The value must be a decimal number between larger than -65 and smaller than 64.

.sendModulationRange(...)

Sends a modulation depth range message to adjust the depth of the modulation wheel's range. The range can be specified with the semitones parameter, the cents parameter or by specifying both parameters at the same time.

Parameters

Signature: sendModulationRange(semitones, [cents], [options])

Parameter	Type(s)	Default	Description
semitones	number		The desired adjustment value in semitones (integer between 0 and 127).
[cents]	number	0	The desired adjustment value in cents (integer between 0 and 127).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendNoteOff(...)

Sends a note off message for the specified notes on the channel. The first parameter is the note. It can be a single value or an array of the following valid values:

• A MIDI note number (integer between 0 and 127)
• A note name, followed by the octave (e.g. "C3", "G#4", "F-1", "Db7")
• A Note object

The execution of the note off command can be delayed by using the time property of the options parameter.

When using Note objects, the release velocity defined in the Note objects has precedence over the one specified via the method's options parameter.

Parameters

Signature: sendNoteOff(note, [options])

Parameter	Type(s)	Default	Description
note	number string Note Array.<number> Array.<string> Array.<Note>		The note(s) to stop. The notes can be specified by using a MIDI note number (0-127), a note identifier (e.g. C3, G#4, F-1, Db7), a Note object or an array of the previous types. When using a note name, octave range must be between -1 and 9. The lowest note is C-1 (MIDI note number 0) and the highest note is G9 (MIDI note number 127).
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.
[options.release]	number	0.5	The velocity at which to release the note (between 0 and 1). If the rawRelease option is also defined, rawRelease will have priority. An invalid velocity value will silently trigger the default of 0.5.
[options.rawRelease]	number	64	The velocity at which to release the note (between 0 and 127). If the release option is also defined, rawRelease will have priority. An invalid velocity value will silently trigger the default of 64.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendNoteOn(...)

Sends a note on message for the specified note(s) on the channel. The first parameter is the note. It can be a single value or an array of the following valid values:

• A Note object

• A MIDI note number (integer between 0 and 127)

• A note identifier (e.g. "C3", "G#4", "F-1", "Db7")

  When passing a Noteobject or a note name, the octaveOffset will be applied. This is not the case when using a note number. In this case, we assume you know exactly which MIDI note number should be sent out.

The execution of the note on command can be delayed by using the time property of the options parameter.

When using Note objects, the attack velocity defined in the Note objects has precedence over the one specified via the method's options parameter. Also, the duration is ignored. If you want to also send a note off message, use the playNote() method instead.

Note: As per the MIDI standard, a note on message with an attack velocity of 0 is functionally equivalent to a note off message.

Parameters

Signature: sendNoteOn(note, [options])

Parameter	Type(s)	Default	Description
note	number string Note Array.<number> Array.<string> Array.<Note>		The note(s) to play. The notes can be specified by using a MIDI note number (0-127), a note identifier (e.g. C3, G#4, F-1, Db7), a Note object or an array of the previous types.
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.
[options.attack]	number	0.5	The velocity at which to play the note (between 0 and 1). If the rawAttack option is also defined, rawAttack will have priority. An invalid velocity value will silently trigger the default of 0.5.
[options.rawAttack]	number	64	The velocity at which to release the note (between 0 and 127). If the attack option is also defined, rawAttack will have priority. An invalid velocity value will silently trigger the default of 64.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendNrpnValue(...)

Sets a non-registered parameter (NRPN) to the specified value. The NRPN is selected by passing in a two-position array specifying the values of the two control bytes. The value is specified by passing in a single integer (most cases) or an array of two integers.

NRPNs are not standardized in any way. Each manufacturer is free to implement them any way they see fit. For example, according to the Roland GS specification, you can control the vibrato rate using NRPN (1, 8). Therefore, to set the vibrato rate value to 123 you would use:

WebMidi.outputs[0].channels[0].sendNrpnValue([1, 8], 123);

In some rarer cases, you need to send two values with your NRPN messages. In such cases, you would use a 2-position array. For example, for its ClockBPM parameter (2, 63), Novation uses a 14-bit value that combines an MSB and an LSB (7-bit values). So, for example, if the value to send was 10, you could use:

WebMidi.outputs[0].channels[0].sendNrpnValue([2, 63], [0, 10]);

For further implementation details, refer to the manufacturer's documentation.

Parameters

Signature: sendNrpnValue(nrpn, [data], [options])

Parameter	Type(s)	Default	Description
nrpn	Array.<number>		A two-position array specifying the two control bytes (0x63, 0x62) that identify the non-registered parameter.
[data]	number Array.<number>	[]	An integer or an array of integers with a length of 1 or 2 specifying the desired data.
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The control value must be between 0 and 127.
• RangeError : The msb value must be between 0 and 127

.sendOmniMode(...)

Sets OMNI mode to "on" or "off". MIDI's OMNI mode causes the instrument to respond to messages from all channels.

It should be noted that support for OMNI mode is not as common as it used to be.

Parameters

Signature: sendOmniMode([state], [options])

Parameter	Type(s)	Default	Description
[state]	boolean	true	Whether to activate OMNI mode (true) or not (false).
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• TypeError : Invalid channel mode message name.
• RangeError : Channel mode controller numbers must be between 120 and 127.
• RangeError : Value must be an integer between 0 and 127.

.sendPitchBend(...)

Sends a MIDI pitch bend message at the scheduled time. The resulting bend is relative to the pitch bend range that has been defined. The range can be set with sendPitchBendRange(). So, for example, if the pitch bend range has been set to 12 semitones, using a bend value of -1 will bend the note 1 octave below its nominal value.

Parameters

Signature: sendPitchBend([value], [options])

Parameter	Type(s)	Default	Description
[value]	number Array.<number>		The intensity of the bend (between -1.0 and 1.0). A value of zero means no bend. If the rawValue option is set to true, the intensity of the bend can be defined by either using a single integer between 0 and 127 (MSB) or an array of two integers between 0 and 127 representing, respectively, the MSB (most significant byte) and the LSB (least significant byte). The MSB is expressed in semitones with 64 meaning no bend. A value lower than 64 bends downwards while a value higher than 64 bends upwards. The LSB is expressed in cents (1/100 of a semitone). An LSB of 64 also means no bend.
[options]	Object	{}
[options.rawValue]	boolean	false	A boolean indicating whether the value should be considered as a float between -1.0 and 1.0 (default) or as raw integer between 0 and 127 (or an array of 2 integers if using both MSB and LSB).
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendPitchBendRange(...)

Sends a pitch bend range message at the scheduled time to adjust the range used by the pitch bend lever. The range is specified by using the semitones and cents parameters. For example, setting the semitones parameter to 12 means that the pitch bend range will be 12 semitones above and below the nominal pitch.

Parameters

Signature: sendPitchBendRange(semitones, [cents], [options])

Parameter	Type(s)	Default	Description
semitones	number		The desired adjustment value in semitones (between 0 and 127). While nothing imposes that in the specification, it is very common for manufacturers to limit the range to 2 octaves (-12 semitones to 12 semitones).
[cents]	number	0	The desired adjustment value in cents (integer between 0-127).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The semitones value must be an integer between 0 and 127.
• RangeError : The cents value must be an integer between 0 and 127.

.sendPolyphonicMode(...)

Sets the polyphonic mode. In "poly" mode (usually the default), multiple notes can be played and heard at the same time. In "mono" mode, only one note will be heard at once even if multiple notes are being played.

Parameters

Signature: sendPolyphonicMode([mode], [options])

Parameter	Type(s)	Default	Description
[mode]	string	poly	The mode to use: "mono" or "poly".
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendProgramChange(...)

Sends a MIDI program change message at the scheduled time.

Parameters

Signature: sendProgramChange([program], [options])

Parameter	Type(s)	Default	Description
[program]	number	1	The MIDI patch (program) number (integer between 0 and 127).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• TypeError : Failed to execute 'send' on 'MIDIOutput': The value at index 1 is greater than 0xFF.

.sendResetAllControllers(...)

Sends a reset all controllers channel mode message. This resets all controllers, such as the pitch bend, to their default value.

Parameters

Signature: sendResetAllControllers([options])

Parameter	Type(s)	Default	Description
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendRpnDecrement(...)

Decrements the specified MIDI registered parameter by 1. Here is the full list of parameter names that can be used with this function:

• Pitchbend Range (0x00, 0x00): "pitchbendrange"
• Channel Fine Tuning (0x00, 0x01): "channelfinetuning"
• Channel Coarse Tuning (0x00, 0x02): "channelcoarsetuning"
• Tuning Program (0x00, 0x03): "tuningprogram"
• Tuning Bank (0x00, 0x04): "tuningbank"
• Modulation Range (0x00, 0x05): "modulationrange"
• Azimuth Angle (0x3D, 0x00): "azimuthangle"
• Elevation Angle (0x3D, 0x01): "elevationangle"
• Gain (0x3D, 0x02): "gain"
• Distance Ratio (0x3D, 0x03): "distanceratio"
• Maximum Distance (0x3D, 0x04): "maximumdistance"
• Maximum Distance Gain (0x3D, 0x05): "maximumdistancegain"
• Reference Distance Ratio (0x3D, 0x06): "referencedistanceratio"
• Pan Spread Angle (0x3D, 0x07): "panspreadangle"
• Roll Angle (0x3D, 0x08): "rollangle"

Parameters

Signature: sendRpnDecrement(parameter, [options])

Parameter	Type(s)	Default	Description
parameter	String Array.<number>		A string identifying the parameter's name (see above) or a two-position array specifying the two control bytes (0x65, 0x64) that identify the registered parameter.
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• TypeError The specified registered parameter is invalid.

.sendRpnIncrement(...)

Increments the specified MIDI registered parameter by 1. Here is the full list of parameter names that can be used with this function:

• Pitchbend Range (0x00, 0x00): "pitchbendrange"
• Channel Fine Tuning (0x00, 0x01): "channelfinetuning"
• Channel Coarse Tuning (0x00, 0x02): "channelcoarsetuning"
• Tuning Program (0x00, 0x03): "tuningprogram"
• Tuning Bank (0x00, 0x04): "tuningbank"
• Modulation Range (0x00, 0x05): "modulationrange"
• Azimuth Angle (0x3D, 0x00): "azimuthangle"
• Elevation Angle (0x3D, 0x01): "elevationangle"
• Gain (0x3D, 0x02): "gain"
• Distance Ratio (0x3D, 0x03): "distanceratio"
• Maximum Distance (0x3D, 0x04): "maximumdistance"
• Maximum Distance Gain (0x3D, 0x05): "maximumdistancegain"
• Reference Distance Ratio (0x3D, 0x06): "referencedistanceratio"
• Pan Spread Angle (0x3D, 0x07): "panspreadangle"
• Roll Angle (0x3D, 0x08): "rollangle"

Parameters

Signature: sendRpnIncrement(parameter, [options])

Parameter	Type(s)	Default	Description
parameter	String Array.<number>		A string identifying the parameter's name (see above) or a two-position array specifying the two control bytes (0x65, 0x64) that identify the registered parameter.
[options]	object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• TypeError The specified registered parameter is invalid.

.sendRpnValue(...)

Sets the specified MIDI registered parameter to the desired value. The value is defined with up to two bytes of data (msb, lsb) that each can go from 0 to 127.

MIDI registered parameters extend the original list of control change messages. The MIDI 1.0 specification lists only a limited number of them:

Numbers	Function
(0x00, 0x00)	pitchbendrange
(0x00, 0x01)	channelfinetuning
(0x00, 0x02)	channelcoarsetuning
(0x00, 0x03)	tuningprogram
(0x00, 0x04)	tuningbank
(0x00, 0x05)	modulationrange
(0x3D, 0x00)	azimuthangle
(0x3D, 0x01)	elevationangle
(0x3D, 0x02)	gain
(0x3D, 0x03)	distanceratio
(0x3D, 0x04)	maximumdistance
(0x3D, 0x05)	maximumdistancegain
(0x3D, 0x06)	referencedistanceratio
(0x3D, 0x07)	panspreadangle
(0x3D, 0x08)	rollangle

Note that the Tuning Program and Tuning Bank parameters are part of the MIDI Tuning Standard, which is not widely implemented.

Parameters

Signature: sendRpnValue(rpn, [data], [options])

Parameter	Type(s)	Default	Description
rpn	string Array.<number>		A string identifying the parameter's name (see above) or a two-position array specifying the two control bytes (e.g. [0x65, 0x64]) that identify the registered parameter.
[data]	number Array.<number>	[]	An single integer or an array of integers with a maximum length of 2 specifying the desired data.
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

.sendTuningBank(...)

Sets the MIDI tuning bank to use. Note that the Tuning Bank parameter is part of the MIDI Tuning Standard, which is not widely implemented.

Parameters

Signature: sendTuningBank(value, [options])

Parameter	Type(s)	Default	Description
value	number		The desired tuning bank (integer between 0 and 127).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The bank value must be between 0 and 127.

.sendTuningProgram(...)

Sets the MIDI tuning program to use. Note that the Tuning Program parameter is part of the MIDI Tuning Standard, which is not widely implemented.

Parameters

Signature: sendTuningProgram(value, [options])

Parameter	Type(s)	Default	Description
value	number		The desired tuning program (integer between 0 and 127).
[options]	Object	{}
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: OutputChannel

Returns the OutputChannel object so methods can be chained.

Throws:

• RangeError : The program value must be between 0 and 127.

.stopNote(...)

Sends a note off message for the specified MIDI note number. The first parameter is the note to stop. It can be a single value or an array of the following valid values:

• A MIDI note number (integer between 0 and 127)
• A note identifier (e.g. "C3", "G#4", "F-1", "Db7")
• A Note object

The execution of the note off command can be delayed by using the time property of the options parameter.

Parameters

Signature: stopNote(note, [options])

Parameter	Type(s)	Default	Description
note	number Note string Array.<number> Array.<Note> Array.<string>		The note(s) to stop. The notes can be specified by using a MIDI note number (0 - 127), a note identifier (e.g. C3, G#4, F-1, Db7) or an array of the previous types. When using a note identifier, octave range must be between -1 and 9. The lowest note is C-1 (MIDI note number 0) and the highest note is G9 (MIDI note number 127).
[options]	Object	{}
[options.release]	number	0.5	The velocity at which to release the note (between 0 and 1). If the rawRelease option is also defined, rawRelease will have priority. An invalid velocity value will silently trigger the default of 0.5.
[options.rawRelease]	number	64	The velocity at which to release the note (between 0 and 127). If the release option is also defined, rawRelease will have priority. An invalid velocity value will silently trigger the default of 64.
[options.time]	number string	(now)	If time is a string prefixed with "+" and followed by a number, the message will be delayed by that many milliseconds. If the value is a positive number (DOMHighResTimeStamp), the operation will be scheduled for that time. The current time can be retrieved with WebMidi.time. If options.time is omitted, or in the past, the operation will be carried out as soon as possible.

Return Value

Returns: Output

Returns the Output object so methods can be chained.

.suspendEvent(...)

Suspends execution of all callbacks functions registered for the specified event type.

You can suspend execution of callbacks registered with EventEmitter.ANY_EVENT by passing EventEmitter.ANY_EVENT to suspendEvent(). Beware that this will not suspend all callbacks but only those registered with EventEmitter.ANY_EVENT. While this may seem counter-intuitive at first glance, it allows the selective suspension of global listeners while leaving other listeners alone. If you truly want to suspends all callbacks for a specific EventEmitter, simply set its eventsSuspended property to true.

Parameters

Signature: suspendEvent(event)

Parameter	Type(s)	Default	Description
event	string Symbol		The event name (or EventEmitter.ANY_EVENT) for which to suspend execution of all callback functions.

.unsuspendEvent(...)

Resumes execution of all suspended callback functions registered for the specified event type.

You can resume execution of callbacks registered with EventEmitter.ANY_EVENT by passing EventEmitter.ANY_EVENT to unsuspendEvent(). Beware that this will not resume all callbacks but only those registered with EventEmitter.ANY_EVENT. While this may seem counter-intuitive, it allows the selective unsuspension of global listeners while leaving other callbacks alone.

Parameters

Signature: unsuspendEvent(event)

Parameter	Type(s)	Default	Description
event	string Symbol		The event name (or EventEmitter.ANY_EVENT) for which to resume execution of all callback functions.

.waitFor(...)

Attributes: async

The waitFor() method is an async function which returns a promise. The promise is fulfilled when the specified event occurs. The event can be a regular event or EventEmitter.ANY_EVENT (if you want to resolve as soon as any event is emitted).

If the duration option is set, the promise will only be fulfilled if the event is emitted within the specified duration. If the event has not been fulfilled after the specified duration, the promise is rejected. This makes it super easy to wait for an event and timeout after a certain time if the event is not triggered.

Parameters

Signature: waitFor(event, [options])

Parameter	Type(s)	Default	Description
event	string Symbol		The event to wait for
[options]	Object	{}
[options.duration]	number	Infinity	The number of milliseconds to wait before the promise is automatically rejected.