DispatchMessage2Listeners

• Author: Renato Miawaki

When you need to dispatch events to methods (listeners) and filter if message is equal.

For socket stream you can use to separate messages and distribute just for clients who want to get the message

For use in stream

const DispatchMessage2Listeners = require('./index') ;

const NmeaBuffer = require( 'nmea-buffer' ) ;
const Stream2Event = require( 'socketstream2event' ) ;

//Example 1, parsing NMea messages
const n1 = new DispatchMessage2Listeners() ;

let s2e = new Stream2Event( 10 ) ;
s2e.addOnData((data)=>{
    let nmeaMessage = NmeaBuffer.parse(data) ;
    n1.dispatchToListeners( nmeaMessage.header, nmeaMessage ) ;
})

n1.showLog = true ;
n1.addListener("a", (d)=>{
    console.log("\n\n*1 recived A in n1", d.message) ;
} ) ;

n1.addListener("B", (d)=>{
    console.log("\n\n*2 recived B in n1", d.message) ;
} ) ;
n1.addListenerAll((d)=>{
    console.log("\n\n*3 recived becouse listener all message in n1", d.message) ;
} ) ;
n1.addListenerAllOnChange((d)=>{
    console.log("\n\n*4 recived listen all if CHANGE in n1", d.message) ;
} ) ;
let data = [ ... NmeaBuffer.getMessageBuffer("a", "just for A, test 1"), ...NmeaBuffer.getMessageBuffer("a", "just for A test 2"), ...NmeaBuffer.getMessageBuffer("B", "just for Bs"), ...NmeaBuffer.getMessageBuffer("c", "just for c"), ...NmeaBuffer.getMessageBuffer("c", "just for c") ];

s2e.parseData(data) ;

console.log("\n End test n1. \n ................................. \n\n") ;

//Exemple 2 - parsing using json with method and body attributes
const n2 = new DispatchMessage2Listeners() ;
s2e.addOnData((data)=>{
    let nmeaMessage = NmeaBuffer.parse(data) ;
    n2.dispatchToListeners( nmeaMessage.header, data ) ;
})
n2.addListener("*",  (d)=>{
    console.log("\n\n*recived * in n2", NmeaBuffer.parse(d)) ;
} )

n2.addListenerOnChange("B",  (d)=>{
    console.log("\n\n*recived B in n2", NmeaBuffer.parse(d)) ;
} )
const Buffer        = require('buffer').Buffer ;

data = [ ... Buffer.from('{"method":"a", "body":"testing 111"}\n'), ... Buffer.from('{"method":"B", "body":"testing 111"}\n') ];

s2e.parseData(data) ;

//if you want to force send message to listeners:

n2.dispatchToListeners("B", "message here")
n2.dispatchToListeners("B", "message here")
n2.dispatchToListeners("B", "message here")

console.log("\n End test n2. \n ................................. \n\n") ;



const n3 = new DispatchMessage2Listeners() ;
var objGroup = {__id:23234234}

n3.addListener("B",  (d)=>{
    console.log("recived B again in n3", d) ;
}, objGroup ) ;

n3.addListenerOnChange("B",  (d)=>{
    console.log("recived B once in n3", d) ;
}, objGroup ) ;

n3.dispatchToListeners("B", "another message again") ;
n3.dispatchToListeners("B", "another message again") ;
n3.dispatchToListeners("B", "another message again") ;
n3.removeListenersByGroup( objGroup ) ;
//just 3 first message neet to recive response
n3.dispatchToListeners("B", "another message again") ;
n3.dispatchToListeners("B", "another message again") ;
n3.dispatchToListeners("B", "another message again") ;

console.log("\n End test n3. \n ................................. \n\n") ;

console.time("n4")
const n4 = new DispatchMessage2Listeners() ;
//when you send object to listeners and need change way to compare:
n4.xcompare = (n1,n2)=>{
    if(!n1 && !n2){
        return true ;
    }
    if(! n1 || !n2 ){
        return false ;
    }
    return (n1.m == n2.m)
}
n4.addListener("C",  (d)=>{
    console.log("recived C again in n4", d) ;
}, objGroup ) ;

n4.addListenerOnChange("C",  (d)=>{
    console.log("recived C once in n4", d) ;
}, objGroup ) ;

for( var i = 0; i < 4; i++){
    n4.dispatchToListeners("C", {m:"another message again"}) ;
}


console.timeEnd("n4")
console.log("\n End test n4. \n ................................. \n\n") ;