Lakutata

English

简体中文

English

简体中文

Appearance

Class: Mutex ​

The lock component: named locks giving a work to one holder at a time, between the instances and the processes of an application as its driver shares them (see MutexDriverOptions). Register it in the components of an application ({class: Mutex, driver: {...}}, named mutex for @Synchronized and the exclusive schedules) and get it with getObject() or @Inject; it is a singleton. Without a driver, the locks are in memory.

A lock is acquired with a random token: only its holder (MutexLock) releases or renews it. The expiring drivers (memory, file, Redis, the table mode of PostgreSQL and MySQL) hold it for its ttl and the component renews it every third of that time, so a crashed holder keeps it at most one ttl. The advisory locks of PostgreSQL and MySQL do not expire: the database releases them when the component's connection closes.

A lock is lost when a renewal finds it expired or taken, when a renewal fails (the store unreachable), or when the connection holding an advisory lock closes: its MutexLock.signal is then aborted with a MutexLostException, and the work it protects should stop. The locks are not reentrant: acquiring a lock this component already holds waits for its release like any other holder.

The driver connects at its first use, not when the component is created: a store which cannot be reached, or whose client package is missing, fails the first acquisition. The component releases the locks it holds and closes the driver when it is destroyed (the application stopping).

Example ​

typescript
import {Application} from 'lakutata'
import {Mutex, type MutexLock} from 'lakutata/com/mutex'

Application
    .run(() => ({
        id: 'mutex.app',
        name: 'Mutex',
        components: {
            //The locks shared by every instance connected to this Redis server
            mutex: {class: Mutex, driver: {type: 'redis', url: 'redis://127.0.0.1:6379'}, ttl: 30000, timeout: 10000}
        }
    }))
    .onLaunched(async (app: Application): Promise<void> => {
        const mutex: Mutex = await app.getObject('mutex')
        //Acquired before the function, released after it, even when it throws
        const total: number = await mutex.synchronized('report:daily', async (lock: MutexLock): Promise<number> => {
            lock.signal.throwIfAborted()
            return 42
        })
        console.log(total)
    })

Extends ​

Constructors ​

Constructor ​

new Mutex(cradleProxy): Mutex

Called by the container only: an object is created through a container (see the class description), never with new.

Parameters ​

cradleProxy ​

Record<string | symbol, any>

The container's resolution proxy.

Returns ​

Mutex

Inherited from ​

Component.constructor

Properties ​

constructor ​

constructor: Function

The initial value of Object.prototype.constructor is the standard built-in Object constructor.

Inherited from ​

Component.constructor

Accessors ​

$id ​

Get Signature ​

get $id(): string | symbol

The name the object was registered under (its key in the module options), or a symbol of its class for an object registered by its class or built without registration.

Returns ​

string | symbol

Inherited from ​

Component.$id

$symbol ​

Get Signature ​

get $symbol(): symbol

A symbol unique to the instance (made from its $uuid), created on first read.

Returns ​

symbol

Inherited from ​

Component.$symbol

$uuid ​

Get Signature ​

get $uuid(): string

A random UUID identifying the instance.

Returns ​

string

Inherited from ​

Component.$uuid

className ​

Get Signature ​

get static className(): string

The name of the class.

Returns ​

string

Inherited from ​

Component.className

className ​

Get Signature ​

get className(): string

The name of the object's class.

Returns ​

string

Inherited from ​

Component.className

heldLocks ​

Get Signature ​

get heldLocks(): MutexLock[]

The locks this component holds now (not released, not lost), in their acquisition order; a new array on each read.

Returns ​

MutexLock[]

Methods ​

[asyncDispose]() ​

[asyncDispose](): Promise<void>

Dispose the object at the end of an await using block, as BaseObject.dispose.

Returns ​

Promise<void>

Resolves once the object is destroyed.

Inherited from ​

Component.[asyncDispose]

acceptsOption() ​

static acceptsOption(name, value): boolean

Whether the class accepts an option which is not one of its @Configurable properties (an option it reads with getConfigurableRecords()): the modules check the options of the objects they declare and warn of the options the classes do not accept. Override it in the classes reading options without configurable properties.

Parameters ​

name ​

string

The option name.

value ​

unknown

The option value.

Returns ​

boolean

true when the option is accepted; false by default.

Inherited from ​

Component.acceptsOption

acquire() ​

acquire(name, options?): Promise<MutexLock>

Acquire a lock, waiting up to the timeout for its holder to release it (or for it to expire). The store is polled: the first retry comes after retryDelay milliseconds, the delay doubling up to one second. The lock is renewed automatically while it is held, until it is released or lost; release it with MutexLock.release, or declare it with await using.

Parameters ​

name ​

string

The lock name, a non-empty string; the component's prefix is added to it in the store.

options? ​

MutexAcquireOptions

The lock's ttl, the timeout of the wait and an abort signal (the component's options by default).

Returns ​

Promise<MutexLock>

The lock acquired.

Throws ​

When the lock is not acquired before the timeout (a timeout of 0 after one attempt).

Throws ​

When the name is not a non-empty string.

Throws ​

When the store fails; the wait stops at the first failure.

Throws ​

When the driver's client package is not installed.

Throws ​

The signal's reason (an AbortError DOMException by default) when the signal is aborted before the lock is acquired.

Example ​

typescript
import type {Mutex, MutexLock} from 'lakutata/com/mutex'

declare const mutex: Mutex

//Waits up to 3 seconds, then rejects with MutexTimeoutException
const lock: MutexLock = await mutex.acquire('order:42', {timeout: 3000})
try {
    console.log(`order 42 is ours, fencing token ${lock.fence}`)
} finally {
    await lock.release()
}

//Released at the end of the block, even when it throws
{
    await using scoped: MutexLock = await mutex.acquire('order:43', {signal: AbortSignal.timeout(5000)})
    console.log(scoped.name)
}

addListener() ​

addListener(event, listener): this

Add a listener called synchronously, at the emitting, after the event's other listeners. Unlike on(), its listener runs before emit() returns.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

listener ​

ListenerFn

The function called with the event's values.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.addListener

assign() ​

Call Signature ​

static assign<T, U>(target, source): T & U

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type Parameters ​
T ​

T extends object

U ​

U

Parameters ​
target ​

T

The target object to copy to.

source ​

U

The source object from which to copy properties.

Returns ​

T & U

Inherited from ​

Component.assign

Call Signature ​

static assign<T, U, V>(target, source1, source2): T & U & V

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type Parameters ​
T ​

T extends object

U ​

U

V ​

V

Parameters ​
target ​

T

The target object to copy to.

source1 ​

U

The first source object from which to copy properties.

source2 ​

V

The second source object from which to copy properties.

Returns ​

T & U & V

Inherited from ​

Component.assign

Call Signature ​

static assign<T, U, V, W>(target, source1, source2, source3): T & U & V & W

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Type Parameters ​
T ​

T extends object

U ​

U

V ​

V

W ​

W

Parameters ​
target ​

T

The target object to copy to.

source1 ​

U

The first source object from which to copy properties.

source2 ​

V

The second source object from which to copy properties.

source3 ​

W

The third source object from which to copy properties.

Returns ​

T & U & V & W

Inherited from ​

Component.assign

Call Signature ​

static assign(target, ...sources): any

Copy the values of all of the enumerable own properties from one or more source objects to a target object. Returns the target object.

Parameters ​
target ​

object

The target object to copy to.

sources ​

...any[]

One or more source objects from which to copy properties

Returns ​

any

Inherited from ​

Component.assign

create() ​

Call Signature ​

static create(o): any

Creates an object that has the specified prototype or that has null prototype.

Parameters ​
o ​

object | null

Object to use as a prototype. May be null.

Returns ​

any

Inherited from ​

Component.create

Call Signature ​

static create(o, properties): any

Creates an object that has the specified prototype, and that optionally contains specified properties.

Parameters ​
o ​

object | null

Object to use as a prototype. May be null

properties ​

PropertyDescriptorMap & ThisType<any>

JavaScript object that contains one or more property descriptors.

Returns ​

any

Inherited from ​

Component.create

defineProperties() ​

static defineProperties<T>(o, properties): T

Adds one or more properties to an object, and/or modifies attributes of existing properties.

Type Parameters ​

T ​

T

Parameters ​

o ​

T

Object on which to add or modify the properties. This can be a native JavaScript object or a DOM object.

properties ​

PropertyDescriptorMap & ThisType<any>

JavaScript object that contains one or more descriptor objects. Each descriptor object describes a data property or an accessor property.

Returns ​

T

Inherited from ​

Component.defineProperties

defineProperty() ​

static defineProperty<T>(o, p, attributes): T

Adds a property to an object, or modifies attributes of an existing property.

Type Parameters ​

T ​

T

Parameters ​

o ​

T

Object on which to add or modify the property. This can be a native JavaScript object (that is, a user-defined object or a built in object) or a DOM object.

p ​

PropertyKey

The property name.

attributes ​

PropertyDescriptor & ThisType<any>

Descriptor for the property. It can be for a data property or an accessor property.

Returns ​

T

Inherited from ​

Component.defineProperty

dispose() ​

dispose(): Promise<void>

Destroy the object: its beforeDestroy(), the objects it created, then its destroy(). Calling it more than once destroys once. A disposed singleton or scoped object is dropped from its container, which creates a new one on the next request. Using a destroyed object (getObject(), buildObject()) throws an ObjectDestroyedException.

Returns ​

Promise<void>

Resolves once the object is destroyed.

Throws ​

The error of the object's own beforeDestroy() or destroy() (an AggregateError when several fail); the errors of the objects it created are reported through the application's logger instead.

Inherited from ​

Component.dispose

emit() ​

emit(event, ...values): boolean

Emit an event: the listeners added by addListener() and onAny() are called now, in order; the ones added by on(), once(), many() and their prepended forms are scheduled (an error they throw is an unhandled rejection). Use emitRequest() to wait for the listeners and their results.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

values ​

...any[]

The values passed to the listeners.

Returns ​

boolean

true when the event has listeners.

Throws ​

The error emitted as an 'error' event which has no listener.

Inherited from ​

Component.emit

emitRequest() ​

emitRequest(event, ...values): Promise<any[]>

Emit an event and wait for its listeners (the asynchronous ones included).

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

values ​

...any[]

The values passed to the listeners.

Returns ​

Promise<any[]>

The results of the listeners, in their order (an empty array without listener).

Throws ​

The first error thrown by a listener, or the error emitted as an 'error' event which has no listener.

Inherited from ​

Component.emitRequest

entries() ​

Call Signature ​

static entries<T>(o): [string, T][]

Returns an array of key/values of the enumerable own properties of an object

Type Parameters ​
T ​

T

Parameters ​
o ​

{[s: string]: T; } | ArrayLike<T>

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

[string, T][]

Inherited from ​

Component.entries

Call Signature ​

static entries(o): [string, any][]

Returns an array of key/values of the enumerable own properties of an object

Parameters ​
o ​

{ }

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

[string, any][]

Inherited from ​

Component.entries

eventNames() ​

eventNames(nsAsArray?): (string | symbol | event[])[]

The events having listeners, in no guaranteed order.

Parameters ​

nsAsArray? ​

boolean

Return each namespaced event as the array of its parts (['order', 'paid']) instead of its name ('order.paid'); false by default.

Returns ​

(string | symbol | event[])[]

The events.

Inherited from ​

Component.eventNames

freeze() ​

Call Signature ​

static freeze<T>(f): T

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type Parameters ​
T ​

T extends Function

Parameters ​
f ​

T

Object on which to lock the attributes.

Returns ​

T

Inherited from ​

Component.freeze

Call Signature ​

static freeze<T, U>(o): Readonly<T>

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type Parameters ​
T ​

T extends object

U ​

U extends string | number | bigint | boolean | symbol

Parameters ​
o ​

T

Object on which to lock the attributes.

Returns ​

Readonly<T>

Inherited from ​

Component.freeze

Call Signature ​

static freeze<T>(o): Readonly<T>

Prevents the modification of existing property attributes and values, and prevents the addition of new properties.

Type Parameters ​
T ​

T

Parameters ​
o ​

T

Object on which to lock the attributes.

Returns ​

Readonly<T>

Inherited from ​

Component.freeze

fromEntries() ​

Call Signature ​

static fromEntries<T>(entries): object

Returns an object created by key-value entries for properties and methods

Type Parameters ​
T ​

T = any

Parameters ​
entries ​

Iterable<readonly [PropertyKey, T]>

An iterable object that contains key-value entries for properties and methods.

Returns ​

object

Inherited from ​

Component.fromEntries

Call Signature ​

static fromEntries(entries): any

Returns an object created by key-value entries for properties and methods

Parameters ​
entries ​

Iterable<readonly any[]>

An iterable object that contains key-value entries for properties and methods.

Returns ​

any

Inherited from ​

Component.fromEntries

getMaxListeners() ​

getMaxListeners(): number

The number of listeners of one event above which a possible memory leak is warned of.

Returns ​

number

The number, 0 for no warning.

Inherited from ​

Component.getMaxListeners

getMethod() ​

getMethod(name, throwExceptionIfNotFound?): (...args) => any

Get a method bound to the object, to call it by name.

Parameters ​

name ​

string | symbol

The method name or symbol.

throwExceptionIfNotFound? ​

boolean

Throw when the method does not exist, instead of returning a function doing nothing; false by default.

Returns ​

The bound method, or a function doing nothing (returning undefined) when it does not exist.

(...args) => any

Throws ​

When the method does not exist and throwExceptionIfNotFound is true.

Inherited from ​

Component.getMethod

getOwnPropertyDescriptor() ​

static getOwnPropertyDescriptor(o, p): PropertyDescriptor | undefined

Gets the own property descriptor of the specified object. An own property descriptor is one that is defined directly on the object and is not inherited from the object's prototype.

Parameters ​

o ​

any

Object that contains the property.

p ​

PropertyKey

Name of the property.

Returns ​

PropertyDescriptor | undefined

Inherited from ​

Component.getOwnPropertyDescriptor

getOwnPropertyDescriptors() ​

static getOwnPropertyDescriptors<T>(o): { [P in string | number | symbol]: TypedPropertyDescriptor<T[P]> } & object

Returns an object containing all own property descriptors of an object

Type Parameters ​

T ​

T

Parameters ​

o ​

T

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

{ [P in string | number | symbol]: TypedPropertyDescriptor<T[P]> } & object

Inherited from ​

Component.getOwnPropertyDescriptors

getOwnPropertyNames() ​

static getOwnPropertyNames(o): string[]

Returns the names of the own properties of an object. The own properties of an object are those that are defined directly on that object, and are not inherited from the object's prototype. The properties of an object include both fields (objects) and functions.

Parameters ​

o ​

any

Object that contains the own properties.

Returns ​

string[]

Inherited from ​

Component.getOwnPropertyNames

getOwnPropertySymbols() ​

static getOwnPropertySymbols(o): symbol[]

Returns an array of all symbol properties found directly on object o.

Parameters ​

o ​

any

Object to retrieve the symbols from.

Returns ​

symbol[]

Inherited from ​

Component.getOwnPropertySymbols

getProperty() ​

getProperty<T>(propertyKey, defaultValue?): T

Read an own property of the object.

Type Parameters ​

T ​

T = any

Parameters ​

propertyKey ​

string

The property name.

defaultValue? ​

T

The value returned when the object has no own property of this name.

Returns ​

T

The property value, or the default value.

Inherited from ​

Component.getProperty

getPrototypeOf() ​

static getPrototypeOf(o): any

Returns the prototype of an object.

Parameters ​

o ​

any

The object that references the prototype.

Returns ​

any

Inherited from ​

Component.getPrototypeOf

hasListeners() ​

hasListeners(event?): boolean

Whether an event has listeners (the wildcard listeners matching it included; the listeners of onAny() excluded).

Parameters ​

event? ​

string | symbol | event[]

The event name, its parts as an array, or a symbol; any event when omitted.

Returns ​

boolean

true when there are listeners.

Inherited from ​

Component.hasListeners

hasMethod() ​

hasMethod(name): boolean

Whether the object has a method of this name or symbol (a function of its class, not an own property).

Parameters ​

name ​

string | symbol

The method name or symbol.

Returns ​

boolean

true when the method exists.

Inherited from ​

Component.hasMethod

hasOwn() ​

static hasOwn(o, v): boolean

Determines whether an object has a property with the specified name.

Parameters ​

o ​

object

An object.

v ​

PropertyKey

A property name.

Returns ​

boolean

Inherited from ​

Component.hasOwn

hasOwnProperty() ​

hasOwnProperty(v): boolean

Determines whether an object has a property with the specified name.

Parameters ​

v ​

PropertyKey

A property name.

Returns ​

boolean

Inherited from ​

Component.hasOwnProperty

hasProperty() ​

hasProperty(propertyKey): boolean

Whether the object has an own property (not a method or accessor of its class) of this name or symbol.

Parameters ​

propertyKey ​

string | symbol

The property name or symbol.

Returns ​

boolean

true when the property exists.

Inherited from ​

Component.hasProperty

is() ​

static is(value1, value2): boolean

Returns true if the values are the same value, false otherwise.

Parameters ​

value1 ​

any

The first value.

value2 ​

any

The second value.

Returns ​

boolean

Inherited from ​

Component.is

isExtensible() ​

static isExtensible(o): boolean

Returns a value that indicates whether new properties can be added to an object.

Parameters ​

o ​

any

Object to test.

Returns ​

boolean

Inherited from ​

Component.isExtensible

isFrozen() ​

static isFrozen(o): boolean

Returns true if existing property attributes and values cannot be modified in an object, and new properties cannot be added to the object.

Parameters ​

o ​

any

Object to test.

Returns ​

boolean

Inherited from ​

Component.isFrozen

isPrototypeOf() ​

isPrototypeOf(v): boolean

Determines whether an object exists in another object's prototype chain.

Parameters ​

v ​

Object

Another object whose prototype chain is to be checked.

Returns ​

boolean

Inherited from ​

Component.isPrototypeOf

isSealed() ​

static isSealed(o): boolean

Returns true if existing property attributes cannot be modified in an object and new properties cannot be added to the object.

Parameters ​

o ​

any

Object to test.

Returns ​

boolean

Inherited from ​

Component.isSealed

keys() ​

Call Signature ​

static keys(o): string[]

Returns the names of the enumerable string properties and methods of an object.

Parameters ​
o ​

object

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

string[]

Inherited from ​

Component.keys

Call Signature ​

static keys(o): string[]

Returns the names of the enumerable string properties and methods of an object.

Parameters ​
o ​

{ }

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

string[]

Inherited from ​

Component.keys

listenerCount() ​

listenerCount(event?): number

The number of listeners of an event (the wildcard listeners matching it included), or of every event (the listeners of onAny() excluded).

Parameters ​

event? ​

string | symbol | event[]

The event name or its parts as an array; every event when omitted.

Returns ​

number

The number of listeners.

Inherited from ​

Component.listenerCount

listeners() ​

listeners(event?): ListenerFn[]

The listeners of an event, or of every event.

Parameters ​

event? ​

string | symbol | event[]

The event name (the wildcard listeners matching it included), its parts as an array, or a symbol; every event when omitted (the listeners of onAny() excluded).

Returns ​

ListenerFn[]

A copy of the listeners; changing it does not change the listeners.

Inherited from ​

Component.listeners

listenersAny() ​

listenersAny(): ListenerFn[]

The listeners of every event, added by onAny() and prependAny().

Returns ​

ListenerFn[]

A copy of these listeners; changing it does not change the listeners.

Inherited from ​

Component.listenersAny

many() ​

many(event, timesToListen, listener): this

Add a listener called for the event's next emittings, then removed.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

timesToListen ​

number

The number of emittings the listener is called for.

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.many

off() ​

off(event, listener): this

Remove a listener of an event; nothing happens when it was not added.

Parameters ​

event ​

string | symbol | event[]

The event the listener was added for.

listener ​

ListenerFn

The listener to remove.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.off

offAny() ​

offAny(listener): this

Remove a listener of every event added by onAny() or prependAny().

Parameters ​

listener ​

ListenerFn

The listener to remove.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.offAny

on() ​

on(event, listener): this

Add a listener, after the event's other listeners.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.on

onAny() ​

onAny(listener): this

Add a listener of every event, called synchronously at the emitting, before the event's own listeners.

Parameters ​

listener ​

EventAndListener

The function called with the event name, then the event's values.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.onAny

once() ​

once(event, listener): this

Add a listener called for the event's next emitting only, then removed.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.once

prependAny() ​

prependAny(listener): this

Add a listener of every event, before the other listeners of every event, called synchronously at the emitting.

Parameters ​

listener ​

EventAndListener

The function called with the event name, then the event's values.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.prependAny

prependListener() ​

prependListener(event, listener): this

Add a listener before the event's other listeners.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.prependListener

prependMany() ​

prependMany(event, timesToListen, listener): this

Add a listener called for the event's next emittings, then removed; it is placed before the event's other listeners.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

timesToListen ​

number

The number of emittings the listener is called for.

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.prependMany

prependOnceListener() ​

prependOnceListener(event, listener): this

Add a listener called for the event's next emitting only, then removed; it is placed before the event's other listeners.

Parameters ​

event ​

string | symbol | event[]

The event: a name ('order.paid', the parts separated by dots, with the wildcards * for one part and ** for any parts) or the parts as an array (['order', 'paid']). A symbol is an event of its own (matched by the wildcard * as a name of one part).

listener ​

ListenerFn

The function called with the event's values, asynchronously after the emitting (in a later turn of the event loop); its result (or the promise it returns) is collected by emitRequest().

Returns ​

this

The component, for chaining.

Inherited from ​

Component.prependOnceListener

preventExtensions() ​

static preventExtensions<T>(o): T

Prevents the addition of new properties to an object.

Type Parameters ​

T ​

T

Parameters ​

o ​

T

Object to make non-extensible.

Returns ​

T

Inherited from ​

Component.preventExtensions

propertyIsEnumerable() ​

propertyIsEnumerable(v): boolean

Determines whether a specified property is enumerable.

Parameters ​

v ​

PropertyKey

A property name.

Returns ​

boolean

Inherited from ​

Component.propertyIsEnumerable

propertyNames() ​

propertyNames(): string[]

The names of the object's own properties (not its class's methods and accessors).

Returns ​

string[]

The names.

Inherited from ​

Component.propertyNames

propertySymbols() ​

propertySymbols(): symbol[]

The symbols of the object's own properties.

Returns ​

symbol[]

The symbols.

Inherited from ​

Component.propertySymbols

reload() ​

reload(): Promise<void>

Destroy the component and initialize it again (same instance): its dependencies are injected again and its init() runs again; its listeners are removed by the teardown. Its configured values are kept.

Returns ​

Promise<void>

Resolves once the component is ready again.

Throws ​

When its parent has been destroyed.

Throws ​

The error of its teardown or of its initialization.

Inherited from ​

Component.reload

removeAllListeners() ​

removeAllListeners(event?): this

Remove the listeners of an event, or all the listeners.

Parameters ​

event? ​

string | symbol | event[]

The event whose listeners are removed; all the listeners when omitted.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.removeAllListeners

removeListener() ​

removeListener(event, listener): this

Remove a listener of an event, as off().

Parameters ​

event ​

string | symbol | event[]

The event the listener was added for.

listener ​

ListenerFn

The listener to remove.

Returns ​

this

The component, for chaining.

Inherited from ​

Component.removeListener

seal() ​

static seal<T>(o): T

Prevents the modification of attributes of existing properties, and prevents the addition of new properties.

Type Parameters ​

T ​

T

Parameters ​

o ​

T

Object on which to lock the attributes.

Returns ​

T

Inherited from ​

Component.seal

setMaxListeners() ​

setMaxListeners(n): void

Set the number of listeners of one event above which a possible memory leak is warned of (the maxListeners option, 11 by default); the listeners are never limited.

Parameters ​

n ​

number

The number, 0 for no warning.

Returns ​

void

Inherited from ​

Component.setMaxListeners

setProperty() ​

setProperty(propertyKey, value): void

Set a property of the object; the value is not validated, even for a @Configurable property.

Parameters ​

propertyKey ​

string

The property name.

value ​

any

The value.

Returns ​

void

Inherited from ​

Component.setProperty

setPrototypeOf() ​

static setPrototypeOf(o, proto): any

Sets the prototype of a specified object o to object proto or null. Returns the object o.

Parameters ​

o ​

any

The object to change its prototype.

proto ​

object | null

The value of the new prototype or null.

Returns ​

any

Inherited from ​

Component.setPrototypeOf

synchronized() ​

synchronized<T>(name, fn, options?): Promise<T>

Run a function holding a lock: acquire it as Mutex.acquire does, run the function, then release the lock whether the function returned or threw (a failure of the release is ignored). When the lock is lost while the function runs, the function is not interrupted: its lock.signal is aborted, and it should check it.

Type Parameters ​

T ​

T

Parameters ​

name ​

string

The lock name, a non-empty string; the component's prefix is added to it in the store.

fn ​

(lock) => T | Promise<T>

The function to run, given the lock.

options? ​

MutexAcquireOptions

The lock's ttl, the timeout of the wait and an abort signal (the component's options by default).

Returns ​

Promise<T>

What the function returns (awaited).

Throws ​

When the lock is not acquired before the timeout; the function does not run.

Throws ​

When the store fails while acquiring the lock.

Throws ​

When the driver's client package is not installed.

Throws ​

The function's error, after the lock is released.

Example ​

typescript
import type {Mutex, MutexLock} from 'lakutata/com/mutex'

declare const mutex: Mutex
declare function chargeOrder(id: number, signal: AbortSignal): Promise<string>

//One payment of order 42 at a time, in every instance sharing the store
const receipt: string = await mutex.synchronized('order:42', (lock: MutexLock): Promise<string> => {
    //Aborted with a MutexLostException when the lock is lost
    return chargeOrder(42, lock.signal)
}, {timeout: 5000})
console.log(receipt)

toLocaleString() ​

toLocaleString(): string

Returns a date converted to a string using the current locale.

Returns ​

string

Inherited from ​

Component.toLocaleString

toString() ​

toString(): string

Returns a string representation of an object.

Returns ​

string

Inherited from ​

Component.toString

tryAcquire() ​

tryAcquire(name, options?): Promise<MutexLock | undefined>

Try to acquire a lock once, without waiting. The lock is renewed automatically while it is held (expiring drivers), until it is released or lost.

Parameters ​

name ​

string

The lock name, a non-empty string; the component's prefix is added to it in the store.

options? ​

Pick<MutexAcquireOptions, "ttl">

ttl: how long the lock stays held without a renewal, in milliseconds (the component's ttl by default).

Returns ​

Promise<MutexLock | undefined>

The lock, or undefined when another holder has it (this component included: the locks are not reentrant).

Throws ​

When the name is not a non-empty string.

Throws ​

When the store fails (unreachable, a failed query).

Throws ​

When the driver's client package (redis, pg, mysql2) is not installed.

Example ​

typescript
import type {Mutex, MutexLock} from 'lakutata/com/mutex'

declare const mutex: Mutex

//A cleanup run by whichever instance gets there first, skipped by the others
const lock: MutexLock | undefined = await mutex.tryAcquire('cleanup')
if (lock) {
    try {
        console.log('cleaning up')
    } finally {
        await lock.release()
    }
}

valueOf() ​

valueOf(): Object

Returns the primitive value of the specified object.

Returns ​

Object

Inherited from ​

Component.valueOf

values() ​

Call Signature ​

static values<T>(o): T[]

Returns an array of values of the enumerable own properties of an object

Type Parameters ​
T ​

T

Parameters ​
o ​

{[s: string]: T; } | ArrayLike<T>

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

T[]

Inherited from ​

Component.values

Call Signature ​

static values(o): any[]

Returns an array of values of the enumerable own properties of an object

Parameters ​
o ​

{ }

Object that contains the properties and methods. This can be an object that you created or an existing Document Object Model (DOM) object.

Returns ​

any[]

Inherited from ​

Component.values

Released under the MIT License.

Copyright © 2023-present Lakutata