Question

为什么要教我编写不带参数的（基本）函数？

function idealSleepHours () {
    const idealHours = 8;
    return idealHours*7
};

它也可以使用参数。我想念什么吗？

   function idealSleepHours (idealHours) {
      idealHours = 8;
      return idealHours * 7
    };

对于一个愚蠢的问题，我感到很抱歉，我是JavaScript（和编程）领域的新人，因此一切对我来说都有些混乱。

编辑：非常感谢您的回答，现在我绝对理解其中的区别。

Answer 1

在JS中，您可以为参数设置默认值。如果不使用该参数，则将采用默认值。

Documentation

function idealHours(idealHours=8){
  return idealHours*8;
}

console.log("Without parameters",idealHours())

console.log("With parameters",idealHours(3))

Answer 2

这里的重点总是在构建应用程序时要保持灵活性

///this function will always return the same result
//because you hard coded the variable inside the function
///so essential isn't an ideal design for a function unless
///it made logical since in your application
function idealSleepHours () {
    const idealHours = 8;
    return idealHours*7
};



/*In the function below you are passing a parameter into the function
which is a  better design of a function, creating flexiablity.
but the problem is you again hard coded the value of idealhours in your function
so there is no need to set it to 8 inside the function 
*/
   function idealSleepHours (idealHours) {
      idealHours = 8;///this line should be omitted
      return idealHours * 7
    };

///making a much better function known as a pure function..

   function idealSleepHours (idealHours) {
      return idealHours * 7
    };
///now you can assign your ideal hours based on any case that might come into mind

idealSleepHours(8)///return 56
idealSleepHours(2)//return 14
idealSleepHours(5)//returns 35

JavaScript代码中的函数参数或无参数

2 个答案: