在JavaScript中命名参数 [英] Named arguments in JavaScript

问题描述

 函数myFunc（a，b，c）
 {
 if（a！= undefined）this.a = a; 
 if（b！= undefined）this.b = b; 
 if（c！= undefined）this.c = c; 
} 
  

我只想设定b的值，然后我可以做一些事情像这样。

  myFunc（undefined，some Value for b，undefined）; 
  

但我想知道是否有办法让我可以这样做来设置值的b

  myFunc（b：一些b值）; 
  

这可能是错误的，但您可能会明白我的意思。我想要指定属性的名称和值，以便我不必担心传递未定义的值。我怎么做到这一点？

也可以随意更改标题，我不知道这个问题应该被调用。

解决方案

是的，传递一个对象字面值

  function myFunc ）
 {
 if（options.a！= undefined）this.a = options.a; 
 if（options.b！= undefined）this.b = options.b; 
 if（options.c！= undefined）this.c = options.c; 
} 
  

并且像这样调用$ / b>

  var var1 = new myFunc（{b：一些值为b}）; 
  

或用于更动态，可扩展的方式（如前所述）

 函数myFunc（obj）
 {
 for（var i in obj）
 {
 if（obj.hasOwnProperty （i））
 {
 this [i] = obj [i]; 
} 
} 
} 
 
 var func = new myFunc（{b：some value for b}）; 
 console.log（func.b）; //一些b的值
  

Say I have a function like this

function myFunc(a, b, c)
{
    if(a!=undefined) this.a = a;
    if(b!=undefined) this.b = b;
    if(c!=undefined) this.c = c;
}

And I want to set only the value for b, then I could do something like this.

myFunc(undefined, "some Value for b", undefined);

But I was wondering if there was a way in which I could do something like this for setting the value of b

myFunc(b:"some value for b");

This is probably wrong, but you probably see what I mean. I want to specify the name of the property along with the value so that I do not have to worry about passing undefined values. How would I do this?

Also feel free to change the title, I have no idea what this question should be called.

解决方案

yes, pass in an object literal

function myFunc(options)
{
    if(options.a!=undefined) this.a = options.a;
    if(options.b!=undefined) this.b = options.b;
    if(options.c!=undefined) this.c = options.c;
}

and call like this

var var1 = new myFunc({b:"some value for b"});

or for a more dynamic, extensible way ( as mentioned)

function myFunc(obj)
{
    for (var i in obj)
    {
        if(obj.hasOwnProperty(i))
        {
            this[i]=obj[i];
        }
    }
}

var func = new myFunc({b:"some value for b"});
console.log(func.b);//"some value for b"

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