是否有一种方法允许“无限”变量的函数在JavaScript?

例子:

load(var1, var2, var3, var4, var5, etc...)
load(var1)

当前回答

使用数组,然后你可以使用你需要的参数。例如,计算数组中元素个数的平均值:

function fncAverage(sample) {
    var lenghtSample = sample.length;
    var elementsSum = 0;
    for (var i = 0; i < lenghtSample; i++) {
        elementsSum = Number(elementsSum) + Number(sample[i]);
    }
    average = elementsSum / lenghtSample
    return (average);
}

console.log(fncAverage([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])); // results 5.5

let mySample = [10, 20, 30, 40];
console.log(fncAverage(mySample)); // results 25

//try your own arrays of numbers

其他回答

使用数组,然后你可以使用你需要的参数。例如,计算数组中元素个数的平均值:

function fncAverage(sample) {
    var lenghtSample = sample.length;
    var elementsSum = 0;
    for (var i = 0; i < lenghtSample; i++) {
        elementsSum = Number(elementsSum) + Number(sample[i]);
    }
    average = elementsSum / lenghtSample
    return (average);
}

console.log(fncAverage([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])); // results 5.5

let mySample = [10, 20, 30, 40];
console.log(fncAverage(mySample)); // results 25

//try your own arrays of numbers

另一种选择是在上下文对象中传入参数。

function load(context)
{
    // do whatever with context.name, context.address, etc
}

像这样使用它

load({name:'Ken',address:'secret',unused:true})

这样做的好处是,您可以添加任意多的命名参数,并且函数可以根据需要使用(或不使用)它们。

请注意,按照Ken的建议传递带有命名属性的Object会增加分配和释放临时对象到每次调用的成本。通过值或引用传递普通参数通常是最有效的。对于许多应用程序,虽然性能不是关键,但对于某些应用程序,它可能是关键。

是的,就像这样:

function load()
{
  var var0 = arguments[0];
  var var1 = arguments[1];
}

load(1,2);

Although I generally agree that the named arguments approach is useful and flexible (unless you care about the order, in which case arguments is easiest), I do have concerns about the cost of the mbeasley approach (using defaults and extends). This is an extreme amount of cost to take for pulling default values. First, the defaults are defined inside the function, so they are repopulated on every call. Second, you can easily read out the named values and set the defaults at the same time using ||. There is no need to create and merge yet another new object to get this information.

function load(context) {
   var parameter1 = context.parameter1 || defaultValue1,
       parameter2 = context.parameter2 || defaultValue2;

   // do stuff
}

这是大致相同数量的代码(可能稍微多一点),但应该是运行时成本的一小部分。