@mangar2/callbacks

Abstract

This module provides a class to manage callbacks . Use it in Classes to support setting callbacks .

Contents

• Meta
• Class Callbacks
  • Parameters
  • Methods
    • hasCallback
    • invokeCallback
    • invokeCallbackAsync
    • on

Meta

File	callbacks.js
Abstract	This module provides a class to manage callbacks . Use it in Classes to support setting callbacks .
Author	Volker Böhm
Copyright	Copyright ( c ) 2020 Volker Böhm
License	This software is licensed under the GNU LESSER GENERAL PUBLIC LICENSE Version 3 . It is furnished "as is" , without any support , and with no warranty , express or implied , as to its usefulness for any purpose .

Class Callbacks

new Callbacks(supportedEvents)

Creates a callback manager to manage callbacks and safely call them

Example

callbacks = new Callbacks(['publish'])
// register a callback
callbacks.on('publish', (param) => { console.log('called publish with ' + param) })
// invoke a callback
callbacks.invokeCallback('publish', 'a parameter')

Callbacks Parameters

Name	Type	Description
supportedEvents	Array.<string>	Names of supported callbacks ( if undefined or null , all callbacks are allowed ) . Use this to prevent a user from registering callbacks with "on" that are not used by your class .

Callbacks Methods

hasCallback

hasCallback (name) => {boolean}

Checks , if a callback is registered

hasCallback Parameters

Name	Type	Description
name	string	name of the callback to look for

hasCallback returns

Type	Description
boolean	true , if the callback is registered

invokeCallback

invokeCallback (event, param) => {any}

Calles a callback stored to an event , if registered

invokeCallback Parameters

Name	Type	Attribute	Description
event	string		event name ( not case sensitive ) for callback
param	any	repeatable	parameters to pass to the callback

invokeCallback returns

Type	Description
any	the result of the callback or null , if the callback is not defined

invokeCallbackAsync

async invokeCallbackAsync (event, param) => {any}

Callcs a callback stored to an event , if registered . It is the async version

invokeCallbackAsync Parameters

Name	Type	Attribute	Description
event	string		event name ( not case sensitive ) for callback
param	any	repeatable	parameters to pass to the callback

invokeCallbackAsync returns

Type	Description
any	the result of the callback or null , if the callback is not defined

on

on (event, callback)

Sets a callback .

on Parameters

Name	Type	Description
event	string	event name ( not case sensitive ) for the callback
callback	function	function ( . . . parameter )

on throws

Type	Description
Error	if the event is not supported
Error	if the callback is not 'function'