why order of parameter remain same even arguments are passed as named arguments? in javascript

问题

for example in python:

def dfde(name,age):
       print(age)
       print(name)
       print(age)

 dfde(age=27,name="dfd")

will give a output as:

27
dfd
27

but samething in javascript will give the output as:

let dfde = function(name, age){
    console.log(age);
    console.log(name);
    console.log(age);
}

dfde(age=27, name="dfd")

will give output as:

dfd
27
dfd

even arguments are passed as named arguments,

why is that?

回答1:

even arguments are passed as named arguments,

There are no named arguments.

dfde(age = 27, name = "dfd")

is the same as:

dfde(27, "dfd")

(Additionally age = 27 creates a new global variable age and assigns the value to it)

---

To use something like named arguments in js you have to pass an obiect literal and deconstruct that:

function dfde({name, age}) {
  console.log(name, age);
}

dfde({ name: "dfd", age: 27 });
// Same as
dfde({ age: 27, name: "dfd" });

回答2:

This happens because there's no named parameters in JavaScript. It recognizes parameters by the order of precedence. So, you should do this:

let dfde = function(name, age){
    console.log(age);
    console.log(name);
    console.log(age);
}

dfde(name="dfd", age=27)  // it just declares variable to global scope as `var`
dfde("dfd", 27) // same as above

You can also, log the way the function is receiving the parameters using arguments like this:

let dfde = function(name, age){
    console.log(arguments);    // no named parameters
}

dfde(name="dfd", age=27) 

If you want to use something like named parameter refer this answer.

来源：https://stackoverflow.com/questions/51259580/why-order-of-parameter-remain-same-even-arguments-are-passed-as-named-arguments