javascript创建函数的20种方式汇总

前端技术 2023/09/03 JavaScript

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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