实际上你已经自己解决了问题，至少差不多：
这适用于做任何事情的任意数量的函数。我正在考虑将plugin.has() 切换为plugin.has("afk","check"); 或类似的东西，所以不是链接函数，它只是一个函数。
但是将变量传递给检查函数会变得很棘手。
嗯，基本上有两种方法：
plugin_with_afk.has("afk","check").check(100); // "check" twice
plugin_with_afk.has("afk","check")(100); // "check" not twice
第一种方法其实很简单：如果插件有“afk”就返回this，否则返回一个有无操作方法的对象check：
Plugin.prototype.has = function(str, member){
if(this.things.indexOf(str) > -1) {
return this;
} else {
var tmp = {}
tmp[member] = function(){}
return tmp;
}
}
plugin_with_afk.has("afk","check").check(1); // has afk, check is there
plugin_without_afk.has("afk","check").check(2); // has no afk, check is no-op
plugin_without_afk.has("nope","check").check(3); // has nope, check is there
这还有一个很大的好处，就是你不需要使用任何函数包装器等等。但是，您必须指定两次使用的函数，如果您不小心使用了另一个名称，这将导致 ReferenceError：
plugin_with_afk.has("afk","check").test(1); // oh oh
那么你能做些什么呢？创建一个简单的函数包装器：
PluginWithFuncRet.prototype.has = function(str,member){
var self = this;
if(this.things.indexOf(str) > -1) {
return function(){
return self[member].apply(self, arguments);
}
} else {
return function(){};
}
}
plugin_with_afk.has("afk","check")(4); // calls check()
plugin_without_afk.has("afk","check")(5);// no-op
就是这样。请注意，您实际上应该将 has 重命名为 use_if 或类似名称，因为它现在所做的不仅仅是检查组件是否存在。
var PluginBase = function(name, things){
this.name = name;
this.things = things;
}
/// First variant
var Plugin = function() {
this.constructor.apply(this, arguments);
}
Plugin.prototype.constructor = PluginBase;
Plugin.prototype.has = function(str,member){
if(this.things.indexOf(str) > -1) {
return this;
} else {
var tmp = {}
tmp[member] = function(){}
return tmp;
}
}
var plugin_with_afk = new Plugin("with afk", ["afk"]);
plugin_with_afk.check = function(val){
console.log("hi", val, this.name);
};
var plugin_without_afk = new Plugin("w/o afk", ["nope"]);
plugin_without_afk.check = function(val){
console.log("nope", val, this.name);
}
/// First variant demo
plugin_with_afk.has("afk","check").check(1)
plugin_without_afk.has("afk","check").check(2)
plugin_without_afk.has("nope","check").check(3)
/// Alternative
var PluginWithFuncRet = function(){
this.constructor.apply(this, arguments);
}
PluginWithFuncRet.prototype.constructor = PluginBase;
PluginWithFuncRet.prototype.has = function(str,member){
var self = this;
if(this.things.indexOf(str) > -1) {
return function(){
return self[member].apply(self,arguments);
}
} else {
return function(){}
}
}
plugin_with_afk = new PluginWithFuncRet("with afk",["afk"]);
plugin_with_afk.check = function(val){
console.log("Hi",val,this.name);
}
plugin_without_afk = new PluginWithFuncRet("w/o afk",["nope"]);
plugin_without_afk.check = function(val){
console.log("Nope",val,this.name);
}
/// Alternative demo
plugin_with_afk.has("afk","check")(4);
plugin_without_afk.has("afk","check")(5);
plugin_without_afk.has("nope","check")(6);
结果：
喜 1 与 afk
不 3 w/o afk
嗨 4 与 afk
不 6 w/o afk