事件分发器的用法如下
生成的事件分发器对象
{_:{start: [{name:call, value: startCallback}]}}
使用apply或call触发事件回调函数，遍历type数组内所有事件type名称，执行value.apply()或value.call(),value内存储对应的回调函数
d3-dispatch
1
2
3
4
5
6
7
8
9
10
// 创建事件分发器 传入参数 事件分发器type
var d = dispatch("start")
// 绑定事件
function startCallback() {console.log('startCallback')}
// type.name
d.on("start.call", startCallback)
// 触发事件
d.call("start");
//d.apply("start");
// {_:{start: [{name:call, value: startCallback}]}}
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
var noop = {value: function() {}};
// 事件分发器工厂
function dispatch() {
for (var i = 0, n = arguments.length, _ = {}, t; i < n; ++i) {
if (!(t = arguments[i] + "") || (t in _)) throw new Error("illegal type: " + t);
_[t] = [];
}
return new Dispatch(_);
}
// 事件分发器构造函数
function Dispatch(_) {
this._ = _;
}
function parseTypenames(typenames, types) {
// 事件分发器类型字符串处理
// 去除开始结束空格，去除特殊字符
return typenames.trim().split(/^|\s+/).map(function(t) {
// type.name 拆分
var name = "", i = t.indexOf(".");
if (i >= 0) name = t.slice(i + 1), t = t.slice(0, i);
if (t && !types.hasOwnProperty(t)) throw new Error("unknown type: " + t);
return {type: t, name: name};
});
}
Dispatch.prototype = dispatch.prototype = {
constructor: Dispatch,
on: function(typename, callback) {
var _ = this._,
T = parseTypenames(typename + "", _),
t,
i = -1,
n = T.length;
// If no callback was specified, return the callback of the given type and name.
if (arguments.length < 2) {
while (++i < n) if ((t = (typename = T[i]).type) && (t = get(_[t], typename.name))) return t;
return;
}
// If a type was specified, set the callback for the given type and name.
// Otherwise, if a null callback was specified, remove callbacks of the given name.
if (callback != null && typeof callback !== "function") throw new Error("invalid callback: " + callback);
while (++i < n) {
if (t = (typename = T[i]).type) _[t] = set(_[t], typename.name, callback);
else if (callback == null) for (t in _) _[t] = set(_[t], typename.name, null);
}
return this;
},
copy: function() {
// 复制_，生成新的dispatch对象
var copy = {}, _ = this._;
for (var t in _) copy[t] = _[t].slice();
return new Dispatch(copy);
},
call: function(type, that) {
if ((n = arguments.length - 2) > 0) for (var args = new Array(n), i = 0, n, t; i < n; ++i) args[i] = arguments[i + 2];
if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
// 遍历执行回调函数
for (t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
},
apply: function(type, that, args) {
if (!this._.hasOwnProperty(type)) throw new Error("unknown type: " + type);
for (var t = this._[type], i = 0, n = t.length; i < n; ++i) t[i].value.apply(that, args);
}
};
function get(type, name) {
for (var i = 0, n = type.length, c; i < n; ++i) {
if ((c = type[i]).name === name) {
return c.value;
}
}
}
function set(type, name, callback) {
for (var i = 0, n = type.length; i < n; ++i) {
if (type[i].name === name) {
type[i] = noop, type = type.slice(0, i).concat(type.slice(i + 1));
break;
}
}
if (callback != null) type.push({name: name, value: callback});
return type;
}