如何将值传递给作为参数的函数

Question

Hello I've come across this piece of code and I have no idea how it works.

function firstFunction(something, else){
     //stuff being done
     return something;
}

var myFunction = firstFunction(function(a,b){
    return a*b;
},'car');

So I am fairly new to Javascript so I'll just say it is, a really confusing language. I understand I am declaring a variable that is assigning the firstFunction to itself and passing some noname function as first parameter and a String as a second one.

How do I go about passing the arguments into that noname functions?

Answer 1

Yes, your assessment is pretty much correct, although the code has a syntax error because you can use else as an identifier. These are referred to as anonymous functions .

Function in JavaScript can be used as parameter values or return values just as easily as any other value. This is what makes them first-class citizens of the language.

The anonymous function you pass in to firstFunction is returned and assigned to myFunction so if you want to call it, you can simply do this:

var result = myFunction(4, 5); // 20