CODEWITHSUNDEEP
javascriptfunction
roma
roma

Reputation: 1

can someone explain please how the value may get passed by the argument?

can someone explain please how it works? when calling the function it logs the "some value" 

function a(pass){
  pass("some value");
}

 a(q=>{
 console.log(q);
});

however if i call the function like this,i get an error "pass is not a function"

function a(pass){
  pass("some value");
}
console.log(a());

and like this,error "argument" is not defined.

function a(pass){
  pass("some value");
}

console.log(a(argument));

Upvotes: 0

Views: 49

Answers (4)

sid
sid

Reputation: 363

You need a pass function because you're calling it when you call function a().

function a(pass){
   pass("some value");
}
console.log(a()); 


function pass(xyz){
   alert('hey');
}

Upvotes: 0

Maheer Ali
Maheer Ali

Reputation: 36564

The function a in the above code is an higher order function. Because it expects another function as argument.

  1. In the first example the first variable is a function so value will a function. So due to pass("some value"); it will be called.

  2. In the second example you donot pass anything to the function a so pass will be undefined. And when you use function calling syntax for any variable which is not a function it will throw error.

  3. In the third example you are trying pass the variable argument to function a. But argument doesn't exist so it throws error.

Upvotes: 0

TheWandererLee
TheWandererLee

Reputation: 1032

Welcome.

1: Here you have passed a function as an argument. The function performs a console.log of the value provided in function a.

2: Here you have provided no function. You are calling a(). There is no definition for a(). There is only a definition for a(pass). You must call it with a parameter. If you do not, it is as if you called a(undefined). Now a tries to do undefined('some value'), throwing error.

3: Here, what is argument? remove the function a() { } code and see you are trying to perform a(argument) but argument is not defined anywhere, and JS cannot determine what is argument.

Upvotes: 0

Jon
Jon

Reputation: 2671

Example 1:

function a(pass){
  pass("some value");
}

 a(q=>{
 console.log(q);
});

In this instance you are passing q=>{console.log(q);} through to the function a. So it calls that and outputs something in the console.

Example 2:

function a(pass){
  pass("some value");
}
console.log(a());

In this case, you are passing no parameter through to function a. So the function attempts to call an undefined parameter which by definition is not a function.

Example 3:

function a(pass){
  pass("some value");
}

console.log(a(argument));

In this case you are passing an undefined variable called argument to function a which results in the error message that you get. I hope this helps.

Upvotes: 1

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