JavaScript method overload effect

In JavaScript methods, there is an array of variables called arguments. It is read-only and all the actual parameter variables passed in
Put it inside, through it, we can type check the incoming parameters to achieve the effect of overloading.
There are two ways to judge the type of a variable.
1. Use the typeof statement:

Copy the codeThe code is as follows:

 
function check(){ 
if(typeof arguments[0] == 'string') 
alert('The argument you passed in is a string');
else if(typeof arguments[0] == 'number') 
alert('The parameter you pass in is a number');
} 

2. Use a property constructor that all JavaScript variables have, which points to the constructor used to construct the variable:

Copy the codeThe code is as follows:

 
function check(){ 
if(arguments[0].constructor == String) 
alert('The argument you passed in is a string');
else if(arguments[0].constructor == Number) 
alert('The parameter you pass in is a number');
} 

Comparison table:
typeof constructor
---------------------------
string String
number Number
object Object
function Function
boolean Boolean
object Array
object User
Through this comparison table, we can see that using typeof cannot accurately determine the specific type, so we use constructor to judge
Break.
First, we define a method to determine the parameter type and number

Copy the codeThe code is as follows:

 
function checkArgs(types,args){ 
// Check the number of parameters
if( != ){ 
return false; 
} 
// Check parameter types
for(var i=0; i<; i++){ 
if(args[i].constructor != types[i]){ 
return false; 
} 
} 
return true; 
} 

We define a method to apply the above method

Copy the codeThe code is as follows:

 
function show(){ 
// Processing parameters is a string call
if(checkArgs([String],arguments)){ 
alert(arguments[0]); 
} 
// Processing parameters is a call to a string and a number
else if(checkArgs([String,Number],arguments)){ 
var s = ''; 
for(var i=0; i<arguments[1]; i++){ 
s+=arguments[0]; 
} 
alert(s); 
// If the parameters do not meet the requirements, give a prompt
}else{ 
alert('Unsupported argument');
} 
} 

When the JavaScript method we define is strict with parameters, we can write code in this way.