I try the observer pattern (by these two Urls: https://davidwalsh.name/pubsub-javascript, http://www.dofactory.com/javascript/observer-design-pattern) but listeners array is empty when I call the publish function.
main.pagination.event= (function () {
var listeners = [];
return {
subscribe: function (fn) {
listeners.push(fn);
return {
unsubscribe: function (fn) {
listeners= listeners.filter(
function (item) {
if (item !== fn) {
return item;
}
}
);
}
};
},
publish: function () {
//it's empty
listeners.forEach(function (item) {
item("...");
});
}
};
})();
main.pagination.init = function () {
$('ul li').click(function () {
main.pagination.event.publish();
};
};
main.update.init = function() {
var event = main.pagination.event.subscribe(main.update.listener);
};
main.update.listener = function (tbl) {
alert(tbl);
};
Thanks for help.
It is empty because you call subscribe
after publish
which does not contain anything inside the listeners
array. Just change the order of the calls like so
main.update.listener = function (tbl) {
alert(tbl);
};
main.pagination.init = function () {
$('ul li').click(function () {
main.pagination.event.publish();
};
};
main.update.init = function() {
var event = main.pagination.event.subscribe(main.update.listener);
};
main.update.init(); // invoke subscribe first to add the listener to the array
main.pagination.init();