javascript创建函数的20种方式汇总

工作中常常会创建一个函数来解决一些需求问题，以下是个人在工作中总结出来的创建函数20种方式，你知道多少？


function sayHello(){
console.log('hello');
}
function leave(){
console.log('goodbye');
}
//test
sayHello();


为完成需求，赶紧声明一个函数吧



var sayHello = function(){
console.log('hello');
}
var leave = function(){
console.log('goodbye');
}
//test
leave();


有求必应，函数表达数来解决



var Action = {
sayHello : function(){
console.log('hello');
},
leave : function(){
console.log('goodbye');
}
}
//test
Action.sayHello();


创建一个方法对象类看起来更整洁



var Action = function(){};
Action.sayHello = function(){
console.log('hello');
}
Action.leave = function(){
console.log('goodbye');
}
//test
Action.sayHello();


为单体添加属性方法，净化命名空间



var Action = function(){
return {
sayHello : function(){
console.log('hello');
},
leave : function(){
console.log('goodbye');
}
}
}
// //test
var a = Action();
a.leave();


返回新对象我们还有更多的事情可以做



var Action = function(){};
Action.prototype.sayHello = function(){
console.log('hello');
}
Action.prototype.leave = function(){
console.log('goodbye');
}
//test
var a = new Action();
a.sayHello();


原型链指向防止创建多次



var Action = function(){};
Action.prototype = {
sayHello : function(){
console.log('hello');
},
leave : function(){
console.log('goodbye');
}
}
//test
var a = new Action();
a.leave();


对象赋给原型看上去更整洁



var Action = function(){
this.sayHello = function(){
console.log('hello');
}
this.leave = function(){
console.log('goodbye');
}
}
//test
var a = new Action();
a.leave();


别忘了还可以在类的内部添加属性



Function.prototype.sayHello = function(){
console.log('hello');
}
Function.prototype.leave = function(){
console.log('leave');
}
//test
var f = function(){};
f.sayHello();


基类原型拓展，新的一片空间



Function.prototype.addMethod = function(name, fn){
this[name] = fn;
}
var methods = function(){};
methods.addMethod('sayHello', function(){
console.log('hello');
});
methods.addMethod('leave', function(){
console.log('leave');
});
//test
methods.sayHello();


通用定义方法函数使用更方便



Function.prototype.addMethod = function(name, fn){
this.prototype[name] = fn;
}
var Methods = function(){};
Methods.addMethod('sayHello', function(){
console.log('hello');
});
Methods.addMethod('leave', function(){
console.log('leave');
});
//test
var a = new Methods();
a.leave();


原形赋值我们还可以用类操作


Function.prototype.addMethod = function(name, fn){
this[name] = fn;
return this;
}
var methods = function(){};
methods.addMethod('sayHello', function(){
console.log('hello');
}).addMethod('leave', function(){
console.log('leave');
});
//test
methods.leave();


链式操作有何不可



Function.prototype.addMethod = function(name, fn){
this.prototype[name] = fn;
return this;
}
var Methods = function(){};
Methods.addMethod('sayHello', function(){
console.log('hello');
}).addMethod('leave', function(){
console.log('leave');
});
//test
var a = new Methods();
a.leave();


原型+链式=更进一步



Function.prototype.addMethod = function(obj){
for(var key in obj){
this[key] = obj[key];
}
}
var methods = function(){};
methods.addMethod({
sayHello : function(){
console.log('hello');
},
leave : function(){
console.log('goodbye');
}
});
//test
methods.leave();


添加对象一次做得更多



Function.prototype.addMethod = function(obj){
for(var key in obj){
this.prototype[key] = obj[key];
}
}
var Methods = function(){};
Methods.addMethod({
sayHello : function(){
console.log('hello');
},
leave : function(){
console.log('goodbye');
}
});
//test
var a = new Methods();
a.leave();


原型有什么不可以



Function.prototype.addMethod = function(obj){
for(var key in obj){
this[key] = obj[key];
}
return this;
}
var methods = function(){};
methods.addMethod({
sayHello : function(){
console.log('hello');
}
}).addMethod({
leave : function(){
console.log('goodbye');
}
});
//test
methods.leave();


函数式添加对象也可以链式操作



Function.prototype.addMethod = function(obj){
for(var key in obj){
this.prototype[key] = obj[key];
}
return this;
}
var Methods = function(){};
Methods.addMethod({
sayHello : function(){
console.log('hello');
}
}).addMethod({
leave : function(){
console.log('goodbye');
}
});
//test
var a = new Methods();
a.leave();


类的链式操作也可以做得更多



Function.prototype.addMethod = function(){
if(arguments.length < 1)
return;
var tostring = Object.prototype.toString;
if(tostring.call(arguments[0]) === '[object Object]'){
for(var key in arguments[0]){
this[key] = arguments[0][key];
}
}else if(typeof arguments[0] === "string" && tostring.call(arguments[1]) === '[object Function]'){
this[arguments[0]] = arguments[1];
}
return this;
}


函数添加封装一下



Function.prototype.addMethod = function(){
if(arguments.length < 1)
return;
var tostring = Object.prototype.toString;
if(tostring.call(arguments[0]) === '[object Object]'){
for(var key in arguments[0]){
this.prototype[key] = arguments[0][key];
}
}else if(typeof arguments[0] === "string" && tostring.call(arguments[1]) === '[object Function]'){
this.prototype[arguments[0]] = arguments[1];
}
return this;
}


类式添加追求的就是个性化



Function.prototype.addMethod = function(){
if(arguments.length < 1)
return;
var cout = 0,
tostring = Object.prototype.toString,
that;
if(typeof arguments[0] === "boolean" && arguments[0]){
cout++;
that = this;
}else{
that = this.prototype;
}
if(tostring.call(arguments[cout]) === '[object Object]'){
for(var key in arguments[cout]){
that[key] = arguments[cout][key];
}
}else if(typeof arguments[cout] === "string" && tostring.call(arguments[cout + 1]) === '[object Function]'){
that[arguments[cout]] = arguments[cout + 1];
}
return this;
}
//text
var Text1 = function(){};
Text1
.addMethod('sayHello', function(){console.log('last say hello!')})
.addMethod('leave', function(){console.log('last goodbye!')});
var t = new Text1();
t.sayHello();
t.leave();
var test2 = function(){};
test2
.addMethod(true, 'sayHello', function(){console.log('last say hello!')})
.addMethod(true, 'leave', function(){console.log('last goodbye!')});
test2.sayHello();
test2.leave();


追求个性化，这么做不必说为什么
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