Mar 30, 2020
How do you override an object in JavaScript with the arguments object


<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">

function add(a){
return a+10;
}
var add=new Function("a","return a+10");
//alert(add(5));
function add(num1,num2){
return num1+num2;
}
var add=new Function("num1","num2","return num1+num2");
alert(add(5,6));
alert(add(5));//The result of this call is NaN: a function with two arguments defined after the time of the call
//This means that even though there is a declaration of var, javascript will overwrite it as long as the variable name is the same
//The previous definition of ======= == concludes that there is no overloading of the function in js.

//-- overloading method with arguments object --
//- call different code blocks depending on the number of parameters, up to 25 parameters
function addNum(){
alert(arguments.length);
for(var x=0;x<arguments.length;x++){
alert(arguments[x]);
//This object can only love the function body
}
if(arguments.length==1){
return arguments[0]+10;
}else if(arguments.length==2){
return arguments[0]+arguments[1];
}else{
return " Parameter error, please check ";
}
}
var value=addNum(10,20,30);
alert(" Return value of the function: "+value);//The value of the result value is: "parameter error, please check"
//In fact, it is through the judgment of parameters, to achieve the call of different functions, and return different values; Doing so similarly implements overloading in Java
//But in essence, js is not overloaded, the same variable, in different places, if the value is assigned, will inevitably overwrite the previously declared variable. Of course,
//This excludes the relationship between the quantities inside the function and the variables outside the function.
</script>
</head>
<body>

</body>
</html>