Class Metronome

Metronome runs a precise timer that can start, pause, and stop.

It has a tempo and time signature, which control how time is counted.

It keeps track of the current position in these units of measurement:

Absolute beat index
By measure and beat, based on time signature which can change

It can be given a score of players with events, which will be played in sync with the metronome.

Example

import { Metronome } from 'mooz/metronome'

Hierarchy

EventEmitter
- Metronome

Constructors

constructor

new Metronome(props?): Metronome
Parameters
- props: {
      audioContext?: AudioContext;
      tempo?: number;
      timeSignature?: MetronomeTimeSignature;
  } = {}
  - Optional audioContext?: AudioContext
  - Optional tempo?: number
  - Optional timeSignature?: MetronomeTimeSignature
Returns Metronome
Overrides EventEmitter.constructor
- Defined in src/metronome/Metronome.ts:94

Properties

audioContext

audioContext: AudioContext

Audio context

listeners

listeners: {} = {}

Type declaration

loopDuration

loopDuration: number = 0

Loop duration by absolute beat index

`Private` nextMeasureListeners

nextMeasureListeners: Function[] = []

Listener callbacks for next measure

position

position: MetronomePosition = ...

Metronome position

`Private` resetPositionScheduled

resetPositionScheduled: boolean = false

Reset position is scheduled

score

score: Score

Current score

tempo

tempo: number = 60

Tempo in beats per minute

timeSignature

timeSignature: MetronomeTimeSignature = ...

Time signature

`Private` timer

timer: PreciseTimer

Precise timer

Methods

destroy

destroy(): void
Destroy instane: stop, remove timer and listeners

Returns void
- Defined in src/metronome/Metronome.ts:348

emit

emit(name, ...args): void
Parameters
- name: any
- Rest ...args: any[]
Returns void
Inherited from EventEmitter.emit
- Defined in src/event/EventEmitter.ts:28

getAbsoluteBeatDuration

getAbsoluteBeatDuration(): number
Get the duration of an absolute beat in seconds

Returns number
- Defined in src/metronome/Metronome.ts:259

getMetronomeBeatDuration

getMetronomeBeatDuration(): number
Get the duration of a metronome beat in seconds

Returns number
- Defined in src/metronome/Metronome.ts:266

off

off(name, listener): void
Parameters
- name: any
- listener: any
Returns void
Inherited from EventEmitter.off
- Defined in src/event/EventEmitter.ts:24

on

on(name, listener): (() => void)
Parameters
- name: any
- listener: any
Returns (() => void)
- - (): void
  - Returns void
Inherited from EventEmitter.on
- Defined in src/event/EventEmitter.ts:11

`Private` onAbsoluteBeat

onAbsoluteBeat(event): void
Callback on absolute beat
Parameters
- event: any
Returns void
- Defined in src/metronome/Metronome.ts:129

`Private` onMetronomeBeat

onMetronomeBeat(event): void
Callback on metronome beat
Parameters
- event: any
Returns void
- Defined in src/metronome/Metronome.ts:206

once

once(name, listener): (() => void)
Parameters
- name: any
- listener: any
Returns (() => void)
- - (): void
  - Returns void
Inherited from EventEmitter.once
- Defined in src/event/EventEmitter.ts:16

pause

pause(): void
Pause the timer

Returns void
- Defined in src/metronome/Metronome.ts:340

removeListeners

removeListeners(): void
Returns void
Inherited from EventEmitter.removeListeners
- Defined in src/event/EventEmitter.ts:33

resetPosition

resetPosition(): void
Reset position

Returns void
- Defined in src/metronome/Metronome.ts:357

schedule

schedule(time, callback, data?): void
Schedule a callback at given time
Parameters
- time: number
- callback: Function
- Optional data: any
Returns void
- Defined in src/metronome/Metronome.ts:364

scheduleNextMeasure

scheduleNextMeasure(callback): void
Schedule a callback for start of next measure
Parameters
- callback: any
Returns void
- Defined in src/metronome/Metronome.ts:376

setLoop

setLoop(duration): void
Set loop duration by absolute beat index
Parameters
- duration: number
Returns void
- Defined in src/metronome/Metronome.ts:122

setScore

setScore(newScore): void
Set current score
Parameters
- newScore: Score
Returns void
- Defined in src/metronome/Metronome.ts:383

setTempo

setTempo(tempo): void
Set tempo in beats per second
- Range: 1~999
Parameters
- tempo: number
Returns void
- Defined in src/metronome/Metronome.ts:394

setTimeSignature

setTimeSignature(timeSignature): void
Set time signature
Parameters
- timeSignature: MetronomeTimeSignature
Returns void
- Defined in src/metronome/Metronome.ts:403

start

start(): void
Start or resume the timer

Returns void
- Defined in src/metronome/Metronome.ts:314

`Private` startLoops

startLoops(firstEvent): void
Start timer loops

There are two loops to count absolute and metronome beats separately.
Parameters
- firstEvent: any
Returns void
- Defined in src/metronome/Metronome.ts:275

stop

stop(): void
Stop the timer

Returns void
- Defined in src/metronome/Metronome.ts:328

Class Metronome

Example

Hierarchy

Index

Constructors

Properties

Methods

Constructors

constructor

Parameters

props: { audioContext?: AudioContext; tempo?: number; timeSignature?: MetronomeTimeSignature; } = {}

Optional audioContext?: AudioContext

Optional tempo?: number

Optional timeSignature?: MetronomeTimeSignature

Returns Metronome

Properties

audioContext

listeners

Type declaration

loopDuration

Private nextMeasureListeners

position

Private resetPositionScheduled

score

tempo

timeSignature

Private timer

Methods

destroy

Returns void

emit

Parameters

name: any

Rest ...args: any[]

Returns void

getAbsoluteBeatDuration

Returns number

getMetronomeBeatDuration

Returns number

off

Parameters

name: any

listener: any

Returns void

on

Parameters

name: any

listener: any

Returns (() => void)

Returns void

Private onAbsoluteBeat

Parameters

event: any

Returns void

Private onMetronomeBeat

Parameters

event: any

Returns void

once

Parameters

name: any

listener: any

Returns (() => void)

Returns void

pause

Returns void

removeListeners

Returns void

resetPosition

Returns void

schedule

Parameters

time: number

callback: Function

Optional data: any

Returns void

scheduleNextMeasure

Parameters

callback: any

Returns void

props: {
audioContext?: AudioContext;
tempo?: number;
timeSignature?: MetronomeTimeSignature;
} = {}

`Optional` audioContext?: AudioContext

`Optional` tempo?: number

`Optional` timeSignature?: MetronomeTimeSignature

`Private` nextMeasureListeners

`Private` resetPositionScheduled

`Private` timer

`Rest` ...args: any[]

`Private` onAbsoluteBeat

`Private` onMetronomeBeat

`Optional` data: any

`Private` startLoops