I have this simple code, while trying to learn the basics of implementing the pubsub method in javascript.
people object emits a simple event and events object is the pubsub, takes the event and emits it to all that listen
Then stats that listens for that event, executes a function, with the data that came from the pubsub.
<html>
<h1>hello</h1>
<script>
var events = {
events:{},
on:function(eventName, fn){
this.events[eventName] = this.events[eventName] || [];
this.events[eventName].push(fn);
},
emit:function (eventName, data) {
if (this.events[eventName]) {
this.events[eventName].forEach(function(fn){
console.log('events this ', this);
fn(data)
});
}
}
}
var stats = (function(){
var counterstats = 0
events.on('peoplechange', setPeople);
function setPeople(a) {
console.log('stats this ', this);
counterstats++;
console.log('stats people ', a )
}
})();
var people = (function(){
console.log('people this ', this);
events.emit('peoplechange', 5);
})();
</script>
</html>
I am asking, how events knows and communicates with setPeople that is inside stats. setPeople is a method of an object, not exposed.
How events sees it? I thought I had to do events.on('peoplechange', events.setPeople); so events knows where this method belongs to.
I print the this of the function in the emit, and the this of the setPeople in the stats and they all point to Window.
I still cannot explain how events sees setPeople inside the stats, without specifying further.
Any explanation would be great. Apologies for asking basic things
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