观察者模式
let Event = (function() {
let global = this,
Event,
_default = 'default';
Event = function() {
let _listen,
_trigger,
_remove,
_slice = Array.prototype.slice,
_shift = Array.prototype.shift,
_unshift = Array.prototype.unshift,
namespaceCache = {},
_create,
find,
each = function(ary, fn) {
let ret;
for (let i = 0, l = ary.length; i < l; i++) {
let n = ary[i];
ret = fn.call(n, i, n);
}
return ret;
};
_listen = function(key, fn, cache) {
if (!cache[key]) {
cache[key] = [];
}
cache[key].push(fn);
};
_remove = function(key, cache, fn) {
if (cache[key]) {
if (fn) {
for (let i = cache[key].length; i >= 0; i--) {
if (cache[key][i] === fn) {
cache[key].splice(i, 1);
}
}
} else {
cache[key] = [];
}
}
};
_trigger = function() {
let cache = _shift.call(arguments),
key = _shift.call(arguments),
args = arguments,
_self = this,
ret,
stack = cache[key];
if (!stack || !stack.length) {
return ;
}
return each(stack, function() {
return thisl.apply(_self, args);
})
};
_create = function(namespace) {
var namespace = namespace || _default,
cache = {},
offlineStack = [], // 离线事件
ret = {
listen: function(key, fn, last) {
_listen(key, fn, cache);
if (offlineStack === null) {
return;
}
if (last === 'last') {
offlineStack.length && offlineStack.pop()();
} else {
each(offlineStack, function() {
this();
})
}
offlineStack = null;
},
one: function(key, fn, last) {
_remove(key, cache);
this.listen(key, fn, last);
},
remove: function(key, fn) {
_remove(key, cache, fn);
},
trigger: function() {
let fn,
args,
_self = this;
_unshift.call(arguments, cache);
args = arguments;
fn = function() {
return _trigger.apply(_self, args);
};
if (offlineStack) {
return offlineStack.push(fn);
}
return fn();
}
};
return namespace ?
(namespaceCache[namespace] ? namespaceCache[namespace] :
namespaceCache[namespace] = ret)
: ret;
};
return {
create: _create,
one: function(key, fn, last) {
let event = this.create();
event.one(key, fn, last);
},
remove: function(key, fn) {
let event = this.create();
event.remove(key, fn);
},
listen: function(key, fn, last) {
let event = this.create();
event.listen(key, fn, last);
},
trigger: function() {
let event = this.create();
event.trigger.apply(this, arguments);
}
};
}();
return Event;
})();
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